ZIP codes and county lines in Tennessee

318 of the 641 ZIP code areas in Tennessee, or 49.6%, overlap more than one county. If your territories, tax rules or service areas are set by county and your list is by ZIP, these are the rows where the two disagree.

ZIP code areas: 641
In more than one county: 318
At least 5% in a second county: 235
Cross a state line: 10

How Tennessee compares

Tennessee ranks 5 of 52 (the 50 states, DC and Puerto Rico) by the share of its ZIP code areas that overlap more than one county. 95 of its counties have at least one split ZIP code area along an edge. 10 of its ZIP code areas also reach into Arkansas, Georgia, Kentucky, Mississippi and Virginia, so a ZIP list that is meant to stop at the state line does not.

Counties with the most split ZIP code areas

Knox County: 16 ZIP codes shared with another county
Davidson County: 14 ZIP codes shared with another county
Giles County: 14 ZIP codes shared with another county
Rutherford County: 14 ZIP codes shared with another county
Bedford County: 13 ZIP codes shared with another county

Every split ZIP code area in Tennessee

Each row is one ZCTA and the counties its land falls in, largest share first. Counties in another state are marked with that state. Sort by the share outside the main county to put the most evenly divided ones first.

	Share of land by county
30741	Walker County, GA 72.3% Catoosa County, GA 27.6% Hamilton County under 0.1%	27.7%	3
37010	Robertson County 61.3% Montgomery County 38.7%	38.7%	2
37012	DeKalb County 57.6% Wilson County 22.0% Smith County 20.4%	42.4%	3
37014	Williamson County 69.4% Rutherford County 30.6%	30.6%	2
37015	Cheatham County 92.7% Davidson County 5.8% Montgomery County 1.5%	7.3%	3
37016	Wilson County 59.1% Cannon County 40.9%	40.9%	2
37018	Coffee County 90.5% Bedford County 9.5%	9.5%	2
37020	Bedford County 75.7% Rutherford County 24.4%	24.4%	2
37022	Sumner County 85.1% Trousdale County 13.3% Macon County 1.6%	14.9%	3
37025	Hickman County 72.9% Dickson County 23.9% Williamson County 3.2%	27.1%	3
37026	Cannon County 96.3% Coffee County 3.7%	3.7%	2
37027	Williamson County 86.4% Davidson County 13.6%	13.6%	2
37030	Smith County 99.8% Jackson County 0.2%	0.2%	2
37031	Sumner County 78.2% Trousdale County 21.8%	21.8%	2
37032	Robertson County 98.4% Cheatham County 1.5% Montgomery County 0.1%	1.6%	3
37033	Hickman County 98.0% Perry County 2.0%	2.0%	2
37034	Marshall County 76.8% Bedford County 23.2%	23.2%	2
37036	Dickson County 93.3% Cheatham County 6.7%	6.7%	2
37043	Montgomery County 98.3% Cheatham County 1.7%	1.7%	2
37046	Williamson County 92.0% Rutherford County 6.3% Marshall County 1.7%	8.0%	3
37047	Marshall County 78.2% Giles County 19.9% Lincoln County 1.9%	21.8%	3
37048	Sumner County 95.8% Robertson County 4.3%	4.3%	2
37049	Robertson County 99.9% Sumner County under 0.1%	under 0.1%	2
37050	Stewart County 51.4% Houston County 26.9% Montgomery County 21.8%	48.6%	3
37051	Dickson County 72.3% Montgomery County 23.8% Houston County 3.9%	27.7%	3
37052	Montgomery County 98.2% Dickson County 1.8%	1.8%	2
37055	Dickson County 91.6% Hickman County 8.4%	8.4%	2
37057	Trousdale County 38.2% Smith County 31.2% Macon County 30.6%	61.8%	3
37060	Rutherford County 74.8% Williamson County 12.7% Bedford County 11.5% Marshall County 1.0%	25.2%	4
37061	Houston County 98.5% Montgomery County 0.9% Stewart County 0.6%	1.4%	3
37062	Williamson County 93.2% Dickson County 6.8% Cheatham County under 0.1%	6.8%	3
37064	Williamson County 99.2% Davidson County 0.8%	0.8%	2
37072	Davidson County 50.7% Sumner County 34.4% Robertson County 14.9%	49.3%	3
37074	Trousdale County 73.7% Macon County 26.3%	26.3%	2
37076	Davidson County 91.9% Wilson County 8.1%	8.1%	2
37078	Humphreys County 97.6% Hickman County 2.4%	2.4%	2
37079	Stewart County 79.8% Montgomery County 20.2%	20.2%	2
37080	Davidson County 59.4% Cheatham County 39.9% Robertson County 0.7%	40.6%	3
37085	Rutherford County 72.6% Wilson County 27.4%	27.4%	2
37086	Rutherford County 94.9% Davidson County 5.1%	5.1%	2
37087	Wilson County 86.8% Smith County 7.4% Trousdale County 5.8%	13.2%	3
37090	Wilson County 96.3% Smith County 2.7% Rutherford County 1.0%	3.7%	3
37091	Marshall County 91.1% Bedford County 7.8% Maury County 1.1%	8.9%	3
37095	DeKalb County 75.8% Cannon County 22.1% Wilson County 2.1%	24.2%	3
37096	Perry County 97.3% Wayne County 2.2% Lewis County 0.5%	2.6%	3
37101	Humphreys County 86.9% Hickman County 8.8% Houston County 4.3%	13.1%	3
37110	Warren County 78.6% Grundy County 14.9% Van Buren County 3.0% Cannon County 1.9% Sequatchie County 1.5%	21.4%	5
37118	Rutherford County 69.3% Wilson County 22.6% Cannon County 8.1%	30.7%	3
37122	Wilson County 90.8% Rutherford County 8.3% Davidson County 0.9%	9.2%	3
37129	Rutherford County 100.0% Wilson County under 0.1%	under 0.1%	2
37135	Williamson County 88.6% Davidson County 8.2% Rutherford County 3.2%	11.4%	3
37138	Davidson County 70.3% Wilson County 29.7%	29.7%	2
37143	Cheatham County 81.4% Davidson County 18.6%	18.6%	2
37144	Lincoln County 58.8% Marshall County 28.0% Bedford County 8.3% Moore County 3.3% Giles County 1.7%	41.2%	5
37145	Smith County 71.0% Macon County 18.7% Jackson County 10.3%	29.0%	3
37146	Robertson County 53.6% Cheatham County 46.4%	46.4%	2
37148	Sumner County 85.2% Robertson County 14.8%	14.8%	2
37149	Rutherford County 57.3% Cannon County 42.7%	42.7%	2
37150	Macon County 54.3% Clay County 40.4% Jackson County 5.3%	45.7%	3
37153	Rutherford County 90.1% Bedford County 9.9%	9.9%	2
37160	Bedford County 97.9% Moore County 2.1%	2.1%	2
37166	DeKalb County 90.8% Warren County 7.5% Cannon County 1.7%	9.2%	3
37171	Montgomery County 99.9% Dickson County under 0.1%	under 0.1%	2
37174	Maury County 74.8% Williamson County 23.7% Marshall County 1.5%	25.2%	3
37175	Houston County 56.6% Stewart County 43.4%	43.4%	2
37178	Houston County 60.9% Stewart County 39.1%	39.1%	2
37180	Bedford County 92.2% Rutherford County 7.3% Marshall County 0.5%	7.8%	3
37181	Dickson County 65.4% Houston County 34.6%	34.6%	2
37183	Bedford County 79.5% Coffee County 15.4% Moore County 5.0%	20.5%	3
37184	Wilson County 96.5% Smith County 3.5%	3.5%	2
37185	Humphreys County 99.8% Houston County 0.2%	0.2%	2
37186	Sumner County 54.0% Macon County 46.0%	46.0%	2
37187	Dickson County 77.7% Cheatham County 22.3%	22.3%	2
37188	Robertson County 73.1% Sumner County 26.9%	26.9%	2
37190	Cannon County 98.5% Warren County 1.5%	1.5%	2
37209	Davidson County 99.8% Cheatham County 0.3%	0.3%	2
37215	Davidson County 98.3% Williamson County 1.6%	1.6%	2
37221	Davidson County 91.9% Williamson County 8.1%	8.1%	2
37306	Franklin County 90.6% Moore County 9.4%	9.4%	2
37307	Polk County 99.0% Bradley County 1.0%	1.0%	2
37308	Hamilton County 63.3% Meigs County 36.7%	36.7%	2
37309	McMinn County 88.5% Polk County 11.5%	11.5%	2
37310	Bradley County 89.1% Polk County 10.9%	10.9%	2
37311	Bradley County 97.9% Hamilton County 2.1%	2.1%	2
37321	Rhea County 95.1% Bledsoe County 4.9%	4.9%	2
37322	Meigs County 91.6% McMinn County 8.4%	8.4%	2
37323	Bradley County 99.7% Polk County 0.3%	0.3%	2
37325	Polk County 87.7% McMinn County 12.3%	12.3%	2
37327	Sequatchie County 82.2% Bledsoe County 16.2% Van Buren County 1.6%	17.8%	3
37328	Lincoln County 95.2% Franklin County 4.8%	4.8%	2
37329	McMinn County 84.5% Monroe County 15.5%	15.5%	2
37330	Franklin County 91.0% Coffee County 9.0%	9.0%	2
37332	Rhea County 94.1% Bledsoe County 5.9%	5.9%	2
37334	Lincoln County 93.1% Moore County 6.5% Bedford County 0.4%	6.9%	3
37335	Lincoln County 97.2% Franklin County 2.8%	2.8%	2
37336	Hamilton County 34.9% Meigs County 34.8% Bradley County 30.3%	65.1%	3
37337	Rhea County 50.3% Cumberland County 43.8% Bledsoe County 5.9%	49.7%	3
37338	Bledsoe County 58.5% Sequatchie County 20.4% Hamilton County 16.0% Rhea County 5.1%	41.5%	4
37352	Moore County 99.2% Franklin County 0.8%	0.8%	2
37353	Bradley County 87.3% Hamilton County 12.7%	12.7%	2
37354	Monroe County 97.0% McMinn County 3.0%	3.0%	2
37356	Marion County 55.8% Grundy County 42.9% Franklin County 1.3%	44.2%	3
37357	Warren County 54.3% Coffee County 28.7% Grundy County 10.4% Cannon County 6.7%	45.8%	4
37359	Lincoln County 80.6% Moore County 19.4%	19.4%	2
37360	Bedford County 60.6% Coffee County 35.1% Moore County 4.3%	39.4%	3
37362	Polk County 79.3% Bradley County 20.7%	20.7%	2
37365	Grundy County 70.6% Sequatchie County 29.4%	29.4%	2
37366	Grundy County 99.5% Franklin County 0.5%	0.5%	2
37367	Bledsoe County 91.8% Cumberland County 4.4% Van Buren County 3.8%	8.2%	3
37369	Polk County 90.4% Monroe County 9.6%	9.6%	2
37373	Hamilton County 99.6% Rhea County 0.4%	0.4%	2
37375	Franklin County 67.5% Marion County 32.5%	32.5%	2
37377	Hamilton County 50.2% Sequatchie County 46.3% Marion County 3.6%	49.8%	3
37379	Hamilton County 87.8% Sequatchie County 6.5% Bledsoe County 5.7%	12.2%	3
37380	Marion County 98.1% Franklin County 1.9%	1.9%	2
37381	Rhea County 79.7% Bledsoe County 20.3%	20.3%	2
37387	Grundy County 68.6% Marion County 31.4%	31.4%	2
37388	Coffee County 42.9% Franklin County 34.0% Moore County 19.8% Bedford County 3.4%	57.1%	4
37397	Marion County 84.5% Sequatchie County 15.5%	15.5%	2
37398	Franklin County 93.9% Moore County 6.1%	6.1%	2
37405	Marion County 75.2% Hamilton County 24.8%	24.8%	2
37419	Marion County 51.4% Hamilton County 48.6%	48.6%	2
37601	Washington County 52.6% Carter County 44.9% Unicoi County 2.5%	47.4%	3
37604	Washington County 94.3% Carter County 5.7%	5.7%	2
37640	Johnson County 63.5% Carter County 36.5%	36.5%	2
37641	Greene County 82.4% Washington County 17.6%	17.6%	2
37642	Hawkins County 99.5% Scott County, VA 0.5%	0.5%	2
37643	Carter County 98.8% Unicoi County 1.2%	1.2%	2
37650	Unicoi County 96.3% Washington County 3.7%	3.7%	2
37656	Washington County 62.8% Greene County 28.9% Sullivan County 8.3%	37.2%	3
37658	Carter County 99.8% Unicoi County 0.2%	0.2%	2
37659	Washington County 99.3% Sullivan County 0.7%	0.7%	2
37660	Sullivan County 90.9% Hawkins County 9.1%	9.1%	2
37663	Sullivan County 95.1% Washington County 4.9%	4.9%	2
37681	Washington County 62.5% Greene County 37.5%	37.5%	2
37686	Sullivan County 99.7% Washington County 0.3%	0.3%	2
37694	Carter County 79.5% Sullivan County 17.9% Washington County 2.6%	20.5%	3
37705	Anderson County 69.3% Union County 30.7%	30.7%	2
37709	Grainger County 98.7% Knox County 1.4%	1.4%	2
37711	Hawkins County 55.1% Greene County 41.1% Hamblen County 3.8%	44.9%	3
37715	Claiborne County 73.2% Campbell County 26.8%	26.8%	2
37721	Knox County 90.1% Union County 9.9%	9.9%	2
37722	Cocke County 85.7% Sevier County 14.3%	14.3%	2
37725	Jefferson County 98.8% Sevier County 1.2%	1.2%	2
37726	Morgan County 87.6% Fentress County 12.4%	12.4%	2
37731	Hawkins County 50.8% Hancock County 49.2%	49.2%	2
37737	Blount County 93.8% Loudon County 6.2%	6.2%	2
37742	Loudon County 67.6% Blount County 32.4%	32.4%	2
37743	Greene County 98.2% Cocke County 1.9%	1.9%	2
37745	Greene County 96.6% Hawkins County 3.4%	3.4%	2
37748	Roane County 70.1% Morgan County 29.9%	29.9%	2
37752	Claiborne County 99.4% Lee County, VA 0.6%	0.6%	2
37754	Anderson County 68.3% Knox County 27.2% Union County 4.4%	31.7%	3
37756	Scott County 87.5% Campbell County 12.5%	12.5%	2
37764	Sevier County 87.2% Knox County 12.6% Jefferson County 0.2%	12.8%	3
37769	Anderson County 83.9% Campbell County 16.1%	16.1%	2
37771	Loudon County 74.7% Roane County 25.4%	25.4%	2
37772	Loudon County 99.9% Knox County 0.1%	0.1%	2
37774	Loudon County 85.8% Roane County 13.0% Monroe County 1.2%	14.3%	3
37779	Union County 95.8% Knox County 4.0% Grainger County 0.2%	4.2%	3
37801	Blount County 88.3% Monroe County 11.7%	11.7%	2
37806	Knox County 88.7% Grainger County 11.3%	11.3%	2
37807	Union County 99.3% Knox County 0.7%	0.7%	2
37811	Hawkins County 98.2% Grainger County 1.9%	1.9%	2
37813	Hamblen County 97.3% Jefferson County 2.7%	2.7%	2
37818	Greene County 99.8% Cocke County 0.2%	0.2%	2
37821	Cocke County 99.8% Jefferson County 0.2%	0.2%	2
37825	Claiborne County 94.8% Union County 5.3%	5.3%	2
37826	McMinn County 98.7% Meigs County 1.3%	1.3%	2
37830	Anderson County 52.1% Roane County 47.7% Knox County 0.2%	47.9%	3
37840	Morgan County 44.3% Anderson County 36.8% Roane County 18.9%	55.7%	3
37846	Loudon County 42.7% Roane County 38.7% Monroe County 14.5% McMinn County 4.0% Meigs County 0.1%	57.3%	5
37847	Campbell County 81.7% Scott County 18.3%	18.3%	2
37848	Grainger County 74.7% Union County 25.4%	25.4%	2
37849	Knox County 71.4% Anderson County 28.6%	28.6%	2
37852	Scott County 90.7% Morgan County 9.3%	9.3%	2
37853	Blount County 91.1% Knox County 8.9%	8.9%	2
37854	Roane County 44.5% Cumberland County 42.1% Morgan County 13.4%	55.5%	3
37857	Hawkins County 99.4% Sullivan County 0.6%	0.6%	2
37865	Sevier County 69.3% Blount County 30.7%	30.7%	2
37869	Hancock County 88.4% Hawkins County 6.7% Claiborne County 4.9%	11.6%	3
37870	Claiborne County 75.3% Campbell County 14.5% Union County 10.2%	24.7%	3
37871	Knox County 45.8% Jefferson County 42.3% Sevier County 11.8%	54.2%	3
37872	Morgan County 86.3% Scott County 13.7%	13.7%	2
37874	Monroe County 70.3% McMinn County 20.5% Loudon County 8.7% Roane County 0.4%	29.7%	4
37876	Sevier County 96.2% Jefferson County 3.8%	3.8%	2
37877	Jefferson County 60.4% Hamblen County 39.6%	39.6%	2
37879	Claiborne County 80.1% Hancock County 19.9%	19.9%	2
37880	Meigs County 57.3% Roane County 42.2% McMinn County 0.6%	42.7%	3
37881	Grainger County 56.1% Hancock County 36.3% Hawkins County 7.1% Claiborne County 0.5%	43.9%	4
37885	Monroe County 98.4% Loudon County 1.6%	1.6%	2
37888	Grainger County 90.8% Union County 9.2%	9.2%	2
37890	Jefferson County 95.7% Hamblen County 4.3%	4.3%	2
37891	Hamblen County 65.5% Hawkins County 34.5%	34.5%	2
37920	Knox County 99.4% Blount County 0.5% Sevier County under 0.1%	0.6%	3
37922	Knox County 99.2% Loudon County 0.8%	0.8%	2
37931	Knox County 91.3% Anderson County 8.7%	8.7%	2
37938	Knox County 99.0% Union County 0.6% Anderson County 0.4%	1.0%	3
38002	Shelby County 86.8% Fayette County 13.2%	13.2%	2
38004	Tipton County 79.2% Shelby County 20.9%	20.9%	2
38006	Haywood County 48.5% Crockett County 45.3% Madison County 6.2%	51.5%	3
38011	Tipton County 96.8% Shelby County 3.1%	3.1%	2
38017	Shelby County 56.9% Fayette County 43.1%	43.1%	2
38028	Fayette County 53.2% Shelby County 46.8%	46.8%	2
38034	Crockett County 65.9% Dyer County 34.1%	34.1%	2
38037	Haywood County 59.2% Lauderdale County 40.8%	40.8%	2
38039	Hardeman County 57.4% Fayette County 42.6%	42.6%	2
38040	Lauderdale County 71.1% Crockett County 19.9% Dyer County 9.0%	28.9%	3
38042	Hardeman County 85.2% Fayette County 14.8%	14.8%	2
38044	Hardeman County 81.3% McNairy County 13.3% Chester County 5.4%	18.7%	3
38049	Fayette County 62.5% Tipton County 37.5%	37.5%	2
38053	Shelby County 92.9% Tipton County 7.1%	7.1%	2
38059	Dyer County 86.6% Gibson County 13.4%	13.4%	2
38061	McNairy County 71.5% Hardeman County 28.5%	28.5%	2
38063	Lauderdale County 90.3% Haywood County 9.7%	9.7%	2
38069	Haywood County 84.3% Tipton County 12.8% Fayette County 2.9%	15.7%	3
38075	Hardeman County 59.0% Haywood County 28.6% Fayette County 12.4%	41.0%	3
38079	Lake County 84.8% Fulton County, KY 15.2%	15.2%	2
38080	Lake County 51.7% Dyer County 45.9% Obion County 2.4%	48.3%	3
38201	Carroll County 59.2% Weakley County 27.5% Henry County 13.3%	40.8%	3
38220	Carroll County 72.3% Gibson County 27.8%	27.8%	2
38224	Henry County 87.9% Weakley County 12.1%	12.1%	2
38229	Weakley County 98.6% Henry County 1.4%	1.4%	2
38233	Gibson County 51.5% Obion County 48.5%	48.5%	2
38237	Weakley County 96.5% Obion County 3.5%	3.5%	2
38240	Obion County 89.5% Dyer County 10.6%	10.6%	2
38242	Henry County 93.8% Weakley County 6.3%	6.3%	2
38255	Weakley County 97.3% Obion County 2.7%	2.7%	2
38257	Obion County 86.0% Weakley County 14.1%	14.1%	2
38259	Obion County 50.5% Dyer County 37.0% Gibson County 12.4%	49.5%	3
38261	Obion County 99.6% Weakley County 0.4%	0.4%	2
38305	Madison County 97.3% Carroll County 2.7%	2.7%	2
38310	McNairy County 69.5% Hardin County 30.5%	30.5%	2
38313	Madison County 55.6% Henderson County 22.3% Chester County 22.1%	44.4%	3
38315	McNairy County 91.0% Chester County 9.0%	9.0%	2
38317	Carroll County 94.1% Benton County 5.9%	5.9%	2
38321	Carroll County 57.8% Henderson County 42.2%	42.2%	2
38326	Hardin County 99.0% Tishomingo County, MS 1.0%	1.0%	2
38328	Henderson County 84.2% Decatur County 15.8%	15.8%	2
38329	Decatur County 94.5% Henderson County 5.5%	5.5%	2
38332	Chester County 86.9% McNairy County 13.1%	13.1%	2
38334	McNairy County 70.1% Chester County 29.9%	29.9%	2
38340	Chester County 87.7% Hardeman County 12.2% McNairy County under 0.1%	12.3%	3
38341	Benton County 76.5% Decatur County 21.5% Carroll County 2.1%	23.6%	3
38343	Gibson County 61.0% Crockett County 21.3% Madison County 17.7%	39.0%	3
38348	Carroll County 98.7% Madison County 1.3%	1.3%	2
38351	Henderson County 99.4% Madison County 0.6%	0.6%	2
38352	Chester County 67.7% Henderson County 32.3%	32.3%	2
38355	Madison County 63.3% Gibson County 36.7%	36.7%	2
38356	Madison County 57.9% Hardeman County 35.5% Chester County 6.5%	42.1%	3
38357	McNairy County 75.1% Hardin County 24.9%	24.9%	2
38359	Hardin County 81.6% McNairy County 14.6% Chester County 3.8%	18.4%	3
38361	Hardin County 91.8% McNairy County 8.2%	8.2%	2
38363	Decatur County 95.8% Henderson County 4.2%	4.2%	2
38366	Madison County 73.0% Chester County 27.0%	27.0%	2
38368	Henderson County 82.7% Chester County 17.4%	17.4%	2
38370	Hardin County 88.3% Henderson County 11.7%	11.7%	2
38371	Henderson County 53.4% Hardin County 42.5% Decatur County 4.1%	46.6%	3
38374	Decatur County 51.3% Henderson County 48.7%	48.7%	2
38376	Hardin County 96.0% McNairy County 4.0%	4.0%	2
38379	McNairy County 90.5% Hardin County 9.6%	9.6%	2
38380	Decatur County 87.0% Benton County 13.0%	13.0%	2
38387	Carroll County 89.2% Benton County 10.8%	10.8%	2
38388	Henderson County 99.4% Decatur County 0.6%	0.6%	2
38390	Carroll County 80.7% Henderson County 19.3%	19.3%	2
38392	Madison County 74.5% Hardeman County 25.6%	25.6%	2
38401	Maury County 96.0% Williamson County 2.1% Marshall County 1.8%	4.0%	3
38425	Wayne County 59.1% Hardin County 26.8% Perry County 14.1%	40.9%	3
38449	Lincoln County 52.6% Giles County 47.4%	47.4%	2
38451	Maury County 81.1% Marshall County 16.9% Giles County 2.1%	18.9%	3
38453	Lincoln County 75.8% Giles County 24.2%	24.2%	2
38456	Lawrence County 70.6% Giles County 29.4%	29.4%	2
38459	Lincoln County 89.0% Giles County 11.0%	11.0%	2
38461	Lewis County 56.9% Maury County 41.5% Hickman County 1.6%	43.1%	3
38462	Lewis County 98.3% Hickman County 1.7%	1.7%	2
38463	Wayne County 77.2% Lawrence County 22.8%	22.8%	2
38464	Lawrence County 81.2% Wayne County 12.1% Giles County 6.3% Lewis County 0.4%	18.8%	4
38468	Lawrence County 92.3% Giles County 7.8%	7.8%	2
38472	Giles County 96.4% Marshall County 3.6%	3.6%	2
38473	Giles County 98.3% Lawrence County 1.7%	1.7%	2
38474	Maury County 86.8% Lewis County 9.3% Giles County 2.2% Lawrence County 1.6%	13.2%	4
38475	Hardin County 77.5% Wayne County 22.5%	22.5%	2
38476	Williamson County 42.3% Hickman County 40.4% Maury County 17.2%	57.7%	3
38478	Giles County 99.9% Lincoln County under 0.1%	under 0.1%	2
38483	Lawrence County 56.8% Lewis County 35.3% Giles County 7.2% Maury County 0.6%	43.2%	4
38485	Wayne County 99.0% Lewis County 1.0%	1.0%	2
38486	Lawrence County 79.7% Wayne County 20.3%	20.3%	2
38487	Maury County 65.0% Hickman County 35.0%	35.0%	2
38501	Putnam County 63.5% Jackson County 35.1% Overton County 1.4%	36.5%	3
38504	Fentress County 84.3% Scott County 15.7%	15.7%	2
38506	Putnam County 70.2% Overton County 25.3% White County 4.0% Jackson County 0.5%	29.8%	4
38541	Overton County 50.1% Clay County 49.9%	49.9%	2
38543	Overton County 88.4% Pickett County 11.6%	11.6%	2
38544	Putnam County 90.6% DeKalb County 9.4%	9.4%	2
38545	Jackson County 67.2% Putnam County 32.8%	32.8%	2
38548	Putnam County 64.4% Smith County 32.8% DeKalb County 2.9%	35.6%	3
38549	Pickett County 93.5% Fentress County 4.9% Clinton County, KY 1.6%	6.5%	3
38551	Clay County 97.6% Jackson County 2.4%	2.4%	2
38556	Fentress County 99.4% Pickett County 0.6%	0.6%	2
38559	Van Buren County 68.9% White County 31.1%	31.1%	2
38564	Jackson County 90.3% Putnam County 9.7%	9.7%	2
38567	Smith County 87.5% DeKalb County 12.5%	12.5%	2
38568	Overton County 56.0% Clay County 33.7% Jackson County 10.3%	44.0%	3
38569	Smith County 52.2% DeKalb County 47.8%	47.8%	2
38572	Cumberland County 91.3% Bledsoe County 8.7%	8.7%	2
38573	Overton County 65.3% Pickett County 33.0% Clay County 1.7%	34.7%	3
38574	Putnam County 48.6% Overton County 32.9% Cumberland County 13.8% Fentress County 4.6%	51.4%	4
38577	Pickett County 56.9% Fentress County 43.1%	43.1%	2
38581	Warren County 53.2% Van Buren County 45.4% DeKalb County 1.4%	46.8%	3
38582	Putnam County 59.0% DeKalb County 41.0%	41.0%	2
38583	White County 82.0% Putnam County 5.6% DeKalb County 5.1% Cumberland County 4.9% Van Buren County 2.4%	18.0%	5
38585	Van Buren County 97.7% Sequatchie County 2.3%	2.3%	2
38588	Jackson County 84.9% Clay County 12.5% Macon County 2.6%	15.1%	3
38589	Fentress County 90.8% Overton County 9.2%	9.2%	2
40965	Bell County, KY 84.9% Claiborne County 15.1%	15.1%	2
42223	Montgomery County 55.1% Christian County, KY 44.9%	44.9%	2
42602	Clinton County, KY 97.7% Russell County, KY 1.3% Wayne County, KY 0.9% Pickett County 0.2%	2.3%	4
72338	Tipton County 66.3% Mississippi County, AR 33.7%	33.7%	2

What to do with this

If a ZIP code in your list is split, the ZIP alone cannot tell you which county an address is in. For most work that is fine. It matters when the county decides something: a sales tax rate, a licence, a franchise agreement written by county, or a service area somebody promised by county name.

The ZIP list audit checks your own list against the same Census data in your browser, and the ZIP spreadsheet comparison covers when a ZIP list is enough and when it is not.

What these numbers are, and are not

A ZCTA is not quite a ZIP code. ZIP Code Tabulation Areas are the Census Bureau's approximations of ZIP code areas, built by grouping census blocks by the ZIP codes of the addresses in them. USPS ZIP codes are delivery routes, not areas, and the two do not always match.
Some ZIP codes have no ZCTA at all. PO box ZIPs, ZIPs for a single building or a single large organisation, and military ZIPs usually have no area of their own, so they cannot be split across counties here and will not match any area in a map.
Land share is not population share. A ZCTA with 20% of its land in a second county might have almost none of its people there, or most of them. The shares here measure area, which is what the Census file publishes.
Tiny overlaps are included. A ZCTA counts as overlapping a county if the Census file lists any part of it there, including slivers along a road or river. That is why the share with at least 5% of land in a second county is shown alongside.

Source: U.S. Census Bureau, 2020 ZCTA to County relationship file, public domain. Counts use 2020 ZCTAs and 2020 county boundaries. ZIP codes added by USPS since then are not in it, and Connecticut's counties have since been replaced by planning regions in Census data.

Route by the boundary, not the ZIP

MapLogics decides who owns an address from a boundary you draw or import, so a ZIP that straddles two counties is answered by where the address actually is. There is a free trial if you want to see it on your own addresses.

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