ZIP codes and county lines in Kentucky

295 of the 782 ZIP code areas in Kentucky, or 37.7%, 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: 782
In more than one county: 295
At least 5% in a second county: 211
Cross a state line: 5

How Kentucky compares

Kentucky ranks 19 of 52 (the 50 states, DC and Puerto Rico) by the share of its ZIP code areas that overlap more than one county. 120 of its counties have at least one split ZIP code area along an edge. 5 of its ZIP code areas also reach into Tennessee, so a ZIP list that is meant to stop at the state line does not.

Counties with the most split ZIP code areas

Graves County: 15 ZIP codes shared with another county
Casey County: 12 ZIP codes shared with another county
Shelby County: 12 ZIP codes shared with another county
Christian County: 11 ZIP codes shared with another county
Jefferson County: 11 ZIP codes shared with another county

Every split ZIP code area in Kentucky

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
38079	Lake County, TN 84.8% Fulton County 15.2%	15.2%	2
38549	Pickett County, TN 93.5% Fentress County, TN 4.9% Clinton County 1.6%	6.5%	3
40003	Shelby County 92.6% Franklin County 7.4%	7.4%	2
40006	Trimble County 98.9% Carroll County 1.1%	1.1%	2
40008	Nelson County 83.4% Spencer County 16.6%	16.6%	2
40009	Marion County 72.6% Taylor County 21.4% Casey County 6.0%	27.4%	3
40011	Henry County 71.2% Trimble County 20.2% Carroll County 8.6%	28.8%	3
40012	Nelson County 77.9% Anderson County 22.1%	22.1%	2
40013	Nelson County 76.6% Spencer County 13.8% Bullitt County 9.6%	23.4%	3
40014	Oldham County 100.0% Jefferson County under 0.1%	under 0.1%	2
40019	Henry County 70.7% Shelby County 29.3%	29.3%	2
40023	Jefferson County 59.8% Spencer County 32.5% Shelby County 7.6%	40.2%	3
40031	Oldham County 93.5% Henry County 6.5%	6.5%	2
40033	Marion County 97.8% Washington County 2.2%	2.2%	2
40037	Marion County 88.0% Nelson County 11.5% Washington County 0.5%	12.0%	3
40045	Trimble County 72.4% Carroll County 27.6%	27.6%	2
40046	Spencer County 75.8% Anderson County 16.9% Shelby County 7.4%	24.2%	3
40047	Bullitt County 95.3% Spencer County 4.3% Jefferson County 0.4%	4.7%	3
40051	Nelson County 67.9% Larue County 28.8% Hardin County 3.3%	32.1%	3
40052	Nelson County 44.8% Larue County 37.2% Marion County 18.0%	55.2%	3
40055	Trimble County 47.7% Henry County 29.5% Oldham County 22.8%	52.3%	3
40057	Henry County 80.3% Shelby County 19.7%	19.7%	2
40059	Oldham County 60.7% Jefferson County 39.3%	39.3%	2
40065	Shelby County 99.5% Spencer County 0.5%	0.5%	2
40068	Henry County 68.6% Shelby County 16.9% Oldham County 14.4%	31.4%	3
40069	Washington County 97.7% Marion County 2.3%	2.3%	2
40071	Spencer County 93.9% Bullitt County 5.0% Shelby County 1.1%	6.1%	3
40075	Henry County 79.0% Carroll County 21.0%	21.0%	2
40076	Shelby County 86.9% Anderson County 8.6% Franklin County 3.7% Spencer County 0.7%	13.1%	4
40109	Bullitt County 97.0% Jefferson County 3.0%	3.0%	2
40119	Breckinridge County 53.7% Grayson County 41.8% Ohio County 4.5%	46.3%	3
40121	Hardin County 84.1% Meade County 15.9%	15.9%	2
40140	Breckinridge County 96.7% Hardin County 3.3%	3.3%	2
40142	Meade County 93.6% Breckinridge County 6.4%	6.4%	2
40146	Breckinridge County 96.7% Meade County 3.3%	3.3%	2
40150	Bullitt County 96.1% Hardin County 3.9%	3.9%	2
40157	Meade County 90.1% Breckinridge County 9.9%	9.9%	2
40171	Breckinridge County 99.4% Meade County 0.6%	0.6%	2
40175	Meade County 45.8% Hardin County 34.7% Breckinridge County 19.5%	54.2%	3
40176	Breckinridge County 64.3% Meade County 35.7%	35.7%	2
40177	Bullitt County 48.6% Hardin County 44.3% Jefferson County 7.2%	51.4%	3
40229	Jefferson County 70.5% Bullitt County 29.6%	29.6%	2
40241	Jefferson County 97.8% Oldham County 2.2%	2.2%	2
40245	Jefferson County 72.2% Shelby County 27.4% Oldham County 0.4%	27.8%	3
40272	Jefferson County 95.6% Bullitt County 4.4%	4.4%	2
40299	Jefferson County 99.4% Bullitt County 0.6%	0.6%	2
40311	Nicholas County 89.3% Bourbon County 9.6% Bath County 0.9% Robertson County 0.3%	10.7%	4
40312	Powell County 99.9% Estill County under 0.1%	under 0.1%	2
40324	Scott County 96.0% Bourbon County 2.2% Fayette County 1.8%	4.0%	3
40328	Marion County 39.2% Boyle County 33.8% Casey County 26.9%	60.8%	3
40330	Mercer County 88.3% Washington County 11.7%	11.7%	2
40336	Estill County 94.0% Lee County 4.3% Jackson County 1.7%	6.0%	3
40342	Anderson County 99.2% Mercer County 0.4% Shelby County 0.4%	0.8%	3
40346	Menifee County 64.0% Bath County 20.1% Montgomery County 15.9%	36.0%	3
40347	Woodford County 76.8% Franklin County 12.4% Scott County 10.7%	23.2%	3
40351	Rowan County 93.8% Elliott County 5.8% Carter County 0.3% Fleming County under 0.1%	6.2%	4
40353	Montgomery County 93.4% Clark County 5.9% Bath County 0.6% Bourbon County 0.1%	6.6%	4
40360	Bath County 96.0% Montgomery County 4.0%	4.0%	2
40361	Bourbon County 97.7% Harrison County 1.2% Fayette County 0.8% Nicholas County 0.3% Montgomery County under 0.1%	2.3%	5
40370	Scott County 77.5% Harrison County 22.5%	22.5%	2
40371	Bath County 77.5% Menifee County 22.5%	22.5%	2
40372	Mercer County 94.3% Anderson County 5.7%	5.7%	2
40374	Bath County 84.1% Nicholas County 11.6% Bourbon County 4.3%	15.9%	3
40379	Scott County 90.0% Franklin County 6.8% Owen County 3.2%	10.0%	3
40380	Powell County 92.3% Estill County 7.7%	7.7%	2
40383	Woodford County 97.2% Jessamine County 2.8%	2.8%	2
40387	Menifee County 77.4% Morgan County 22.6%	22.6%	2
40391	Clark County 99.3% Fayette County 0.7%	0.7%	2
40403	Madison County 76.5% Garrard County 14.4% Rockcastle County 9.1%	23.5%	3
40409	Rockcastle County 94.5% Lincoln County 3.4% Pulaski County 2.1%	5.5%	3
40419	Lincoln County 55.7% Garrard County 20.9% Rockcastle County 18.3% Pulaski County 5.2%	44.3%	4
40422	Boyle County 94.2% Lincoln County 5.8%	5.8%	2
40437	Casey County 52.4% Lincoln County 47.6%	47.6%	2
40440	Boyle County 99.9% Lincoln County 0.1%	0.1%	2
40442	Lincoln County 53.8% Casey County 46.2%	46.2%	2
40444	Garrard County 96.6% Lincoln County 3.4%	3.4%	2
40447	Jackson County 94.5% Owsley County 4.1% Estill County 0.7% Rockcastle County 0.7%	5.5%	4
40461	Garrard County 65.4% Madison County 34.6%	34.6%	2
40464	Boyle County 72.1% Casey County 27.9%	27.9%	2
40468	Boyle County 79.0% Washington County 14.3% Mercer County 6.7%	21.0%	3
40484	Lincoln County 96.4% Garrard County 2.7% Casey County 0.9%	3.6%	3
40486	Jackson County 90.5% Owsley County 8.1% Clay County 1.4%	9.5%	3
40489	Lincoln County 85.5% Casey County 14.5%	14.5%	2
40509	Fayette County 91.5% Clark County 8.5%	8.5%	2
40511	Fayette County 91.0% Scott County 4.9% Bourbon County 4.1%	9.0%	3
40515	Fayette County 85.5% Clark County 8.0% Jessamine County 6.5%	14.5%	3
40516	Fayette County 86.3% Bourbon County 13.7%	13.7%	2
40601	Franklin County 88.7% Woodford County 5.9% Shelby County 4.4% Henry County 0.9%	11.3%	4
40701	Whitley County 61.4% Laurel County 20.2% Knox County 18.3%	38.6%	3
40734	Knox County 95.6% Laurel County 4.4%	4.4%	2
40741	Laurel County 96.9% Clay County 3.1%	3.1%	2
40744	Laurel County 97.7% Clay County 2.3%	2.3%	2
40759	Whitley County 84.5% Knox County 15.4%	15.4%	2
40763	Whitley County 88.0% Knox County 12.0%	12.0%	2
40769	Whitley County 93.5% McCreary County 6.5%	6.5%	2
40771	Knox County 86.5% Whitley County 13.4%	13.4%	2
40808	Leslie County 85.4% Harlan County 14.6%	14.6%	2
40810	Harlan County 90.4% Leslie County 9.6%	9.6%	2
40823	Harlan County 99.9% Letcher County 0.1%	0.1%	2
40874	Leslie County 81.5% Clay County 18.5%	18.5%	2
40906	Knox County 97.7% Whitley County 2.3%	2.3%	2
40913	Bell County 67.7% Clay County 32.3%	32.3%	2
40914	Clay County 71.6% Leslie County 28.4%	28.4%	2
40939	Bell County 99.2% Knox County 0.8%	0.8%	2
40940	Bell County 54.1% Whitley County 45.9%	45.9%	2
40962	Clay County 99.8% Laurel County 0.2%	0.2%	2
40965	Bell County 84.9% Claiborne County, TN 15.1%	15.1%	2
40972	Clay County 98.8% Leslie County 1.2%	1.2%	2
40983	Owsley County 58.1% Clay County 41.9%	41.9%	2
40988	Bell County 95.3% Harlan County 4.7%	4.7%	2
41003	Harrison County 74.1% Pendleton County 20.6% Grant County 5.4%	25.9%	3
41004	Bracken County 93.7% Robertson County 5.9% Pendleton County 0.4%	6.3%	3
41006	Pendleton County 87.9% Campbell County 12.1%	12.1%	2
41007	Campbell County 89.5% Pendleton County 10.5%	10.5%	2
41008	Carroll County 95.6% Trimble County 4.4%	4.4%	2
41010	Grant County 43.3% Owen County 39.4% Harrison County 14.9% Scott County 2.5%	56.7%	4
41018	Kenton County 77.1% Boone County 22.9%	22.9%	2
41030	Grant County 62.4% Kenton County 29.3% Boone County 7.5% Pendleton County 0.8%	37.6%	4
41031	Harrison County 90.9% Nicholas County 5.7% Bourbon County 3.4% Robertson County under 0.1%	9.1%	4
41033	Pendleton County 82.6% Kenton County 17.4%	17.4%	2
41034	Mason County 97.6% Bracken County 2.4%	2.4%	2
41035	Grant County 97.0% Pendleton County 1.5% Owen County 1.5%	3.0%	3
41039	Fleming County 84.7% Nicholas County 10.7% Mason County 2.4% Robertson County 2.2%	15.3%	4
41040	Pendleton County 95.6% Bracken County 4.4%	4.4%	2
41042	Boone County 94.6% Kenton County 5.4%	5.4%	2
41043	Bracken County 71.8% Pendleton County 28.2%	28.2%	2
41044	Mason County 39.0% Robertson County 31.0% Bracken County 30.1%	61.0%	3
41045	Carroll County 64.6% Gallatin County 35.4%	35.4%	2
41046	Owen County 45.3% Gallatin County 36.9% Grant County 17.8%	54.7%	3
41049	Fleming County 99.8% Rowan County 0.3%	0.3%	2
41052	Grant County 52.9% Owen County 47.1%	47.1%	2
41055	Mason County 89.1% Fleming County 6.7% Robertson County 4.2%	10.9%	3
41056	Mason County 98.2% Lewis County 1.3% Fleming County 0.5%	1.8%	3
41064	Robertson County 93.7% Bracken County 5.5% Harrison County 0.8%	6.3%	3
41083	Carroll County 62.2% Gallatin County 30.5% Owen County 7.3%	37.8%	3
41086	Gallatin County 53.5% Owen County 46.5%	46.5%	2
41092	Boone County 65.0% Gallatin County 33.1% Grant County 1.8%	35.0%	3
41093	Fleming County 81.4% Lewis County 18.6%	18.6%	2
41094	Boone County 63.0% Kenton County 37.0%	37.0%	2
41097	Grant County 87.5% Pendleton County 12.5%	12.5%	2
41098	Owen County 83.7% Carroll County 16.3%	16.3%	2
41101	Boyd County 82.7% Greenup County 17.3%	17.3%	2
41102	Boyd County 89.0% Greenup County 9.7% Carter County 1.4%	11.0%	3
41129	Boyd County 78.6% Lawrence County 21.4%	21.4%	2
41132	Carter County 93.5% Lawrence County 6.5%	6.5%	2
41141	Lewis County 57.3% Greenup County 42.7% Carter County under 0.1%	42.7%	3
41143	Carter County 90.4% Greenup County 9.6%	9.6%	2
41164	Carter County 77.1% Elliott County 22.3% Lewis County 0.4% Rowan County 0.1%	22.9%	4
41168	Boyd County 64.6% Carter County 35.4%	35.4%	2
41174	Greenup County 73.6% Lewis County 26.4%	26.4%	2
41180	Lawrence County 74.1% Elliott County 20.8% Carter County 5.2%	25.9%	3
41216	Floyd County 66.4% Johnson County 33.6%	33.6%	2
41219	Johnson County 96.1% Morgan County 3.9%	3.9%	2
41230	Lawrence County 96.7% Martin County 3.3%	3.3%	2
41232	Lawrence County 69.1% Johnson County 30.9%	30.9%	2
41254	Johnson County 92.3% Lawrence County 7.7%	7.7%	2
41265	Johnson County 79.8% Floyd County 20.2%	20.2%	2
41301	Wolfe County 84.3% Breathitt County 8.0% Lee County 7.8%	15.7%	3
41311	Lee County 98.6% Owsley County 0.9% Breathitt County 0.4%	1.4%	3
41314	Owsley County 74.8% Breathitt County 25.2% Lee County under 0.1%	25.2%	3
41332	Morgan County 61.4% Wolfe County 38.6%	38.6%	2
41339	Breathitt County 92.0% Knott County 6.6% Lee County 1.4%	8.0%	3
41360	Wolfe County 98.9% Powell County 1.1%	1.1%	2
41425	Morgan County 98.8% Wolfe County 1.2%	1.2%	2
41472	Morgan County 99.1% Elliott County 0.9%	0.9%	2
41514	Pike County 98.0% Martin County 2.0%	2.0%	2
41537	Letcher County 50.8% Pike County 49.2%	49.2%	2
41605	Floyd County 72.8% Pike County 27.3%	27.3%	2
41630	Floyd County 54.1% Knott County 45.9%	45.9%	2
41640	Knott County 56.1% Floyd County 35.4% Magoffin County 8.5%	43.9%	3
41659	Pike County 74.3% Floyd County 25.7%	25.7%	2
41701	Perry County 78.5% Knott County 21.5%	21.5%	2
41721	Perry County 77.0% Owsley County 11.6% Breathitt County 11.3%	23.0%	3
41722	Knott County 79.0% Perry County 21.0%	21.0%	2
41723	Perry County 77.4% Leslie County 22.6%	22.6%	2
41731	Perry County 76.2% Letcher County 23.8%	23.8%	2
41745	Perry County 84.2% Breathitt County 15.8%	15.8%	2
41754	Perry County 81.1% Leslie County 18.9%	18.9%	2
41759	Knott County 99.8% Perry County 0.2%	0.2%	2
41773	Knott County 50.4% Perry County 49.6%	49.6%	2
42003	McCracken County 99.2% Graves County 0.8%	0.8%	2
42021	Carlisle County 90.2% Hickman County 9.8%	9.8%	2
42025	Marshall County 96.1% Graves County 2.4% Calloway County 1.6%	3.9%	3
42027	Graves County 85.6% McCracken County 14.4%	14.4%	2
42035	Carlisle County 77.8% Graves County 22.2%	22.2%	2
42036	Calloway County 98.7% Marshall County 1.4%	1.4%	2
42038	Lyon County 98.5% Caldwell County 1.5%	1.5%	2
42039	Graves County 34.2% Hickman County 33.0% Carlisle County 32.8%	65.8%	3
42040	Graves County 79.7% Calloway County 20.3%	20.3%	2
42041	Fulton County 49.4% Graves County 27.9% Hickman County 22.7%	50.6%	3
42048	Marshall County 92.9% Calloway County 7.1%	7.1%	2
42049	Calloway County 99.2% Graves County 0.8%	0.8%	2
42053	Ballard County 50.9% McCracken County 49.1%	49.1%	2
42054	Calloway County 86.0% Marshall County 9.8% Graves County 4.3%	14.1%	3
42064	Crittenden County 95.6% Caldwell County 4.4%	4.4%	2
42066	Graves County 98.2% Marshall County 1.7% Calloway County 0.2%	1.9%	3
42069	Graves County 79.4% McCracken County 20.6%	20.6%	2
42071	Calloway County 99.5% Graves County 0.6%	0.6%	2
42078	Livingston County 75.6% Crittenden County 24.4%	24.4%	2
42082	Graves County 55.5% Marshall County 30.8% McCracken County 13.8%	44.5%	3
42085	Graves County 56.7% Hickman County 43.3%	43.3%	2
42088	Graves County 80.5% Hickman County 19.6%	19.6%	2
42101	Warren County 88.5% Edmonson County 8.2% Butler County 3.3%	11.5%	3
42104	Warren County 91.3% Simpson County 8.7%	8.7%	2
42122	Warren County 94.6% Allen County 5.4%	5.4%	2
42127	Barren County 85.1% Hart County 14.9%	14.9%	2
42129	Metcalfe County 95.1% Adair County 4.9%	4.9%	2
42133	Monroe County 43.4% Barren County 32.2% Allen County 24.4%	56.6%	3
42134	Simpson County 93.3% Allen County 6.8%	6.8%	2
42154	Metcalfe County 87.2% Barren County 12.8%	12.8%	2
42160	Edmonson County 55.3% Barren County 44.7%	44.7%	2
42166	Metcalfe County 61.2% Barren County 24.4% Monroe County 14.5%	38.8%	3
42167	Monroe County 97.7% Cumberland County 1.3% Metcalfe County 1.0%	2.3%	3
42170	Warren County 50.8% Simpson County 49.2%	49.2%	2
42171	Warren County 47.7% Edmonson County 27.7% Barren County 24.6%	52.3%	3
42202	Logan County 97.8% Simpson County 2.2%	2.2%	2
42204	Todd County 71.7% Logan County 28.3%	28.3%	2
42206	Logan County 86.3% Simpson County 12.6% Warren County 1.1%	13.7%	3
42207	Edmonson County 97.3% Grayson County 2.7%	2.7%	2
42211	Trigg County 99.8% Caldwell County 0.2%	0.2%	2
42214	Metcalfe County 81.5% Green County 18.6%	18.6%	2
42215	Christian County 73.4% Trigg County 26.6%	26.6%	2
42220	Todd County 98.6% Christian County 1.1% Muhlenberg County 0.2%	1.4%	3
42223	Montgomery County, TN 55.1% Christian County 44.9%	44.9%	2
42232	Christian County 73.1% Trigg County 26.9%	26.9%	2
42236	Christian County 92.7% Trigg County 7.3%	7.3%	2
42256	Logan County 61.4% Butler County 24.2% Todd County 12.1% Muhlenberg County 2.3%	38.6%	4
42265	Logan County 87.8% Todd County 12.2%	12.2%	2
42266	Christian County 87.9% Todd County 12.1%	12.1%	2
42274	Warren County 88.7% Logan County 11.3%	11.3%	2
42275	Butler County 72.4% Edmonson County 27.6%	27.6%	2
42276	Logan County 99.9% Butler County 0.1%	0.1%	2
42286	Todd County 94.3% Christian County 5.7%	5.7%	2
42301	Daviess County 95.3% Henderson County 4.2% McLean County 0.5%	4.7%	3
42320	Ohio County 92.5% Butler County 7.5%	7.5%	2
42327	McLean County 99.0% Daviess County 1.0%	1.0%	2
42333	Ohio County 94.9% Butler County 5.1%	5.1%	2
42339	Muhlenberg County 82.6% Butler County 17.4%	17.4%	2
42343	Ohio County 76.3% Hancock County 20.8% Breckinridge County 3.0%	23.7%	3
42345	Muhlenberg County 99.4% Todd County 0.6%	0.6%	2
42348	Hancock County 88.3% Daviess County 11.7%	11.7%	2
42349	Ohio County 89.9% Grayson County 10.1%	10.1%	2
42351	Hancock County 76.3% Daviess County 23.7%	23.7%	2
42352	McLean County 59.4% Ohio County 40.6%	40.6%	2
42361	Ohio County 69.2% Grayson County 30.8%	30.8%	2
42366	Daviess County 94.8% Ohio County 4.2% Hancock County 1.1%	5.3%	3
42368	Hancock County 55.6% Ohio County 44.4%	44.4%	2
42372	McLean County 71.9% Muhlenberg County 28.1%	28.1%	2
42376	Daviess County 80.9% Ohio County 10.6% McLean County 8.5%	19.1%	3
42378	Ohio County 63.1% Daviess County 36.9%	36.9%	2
42404	Webster County 94.2% Union County 5.8%	5.8%	2
42406	Henderson County 99.9% Webster County under 0.1%	under 0.1%	2
42408	Hopkins County 58.2% Caldwell County 26.6% Christian County 15.2%	41.8%	3
42411	Caldwell County 68.2% Crittenden County 24.3% Lyon County 7.5%	31.8%	3
42437	Union County 97.1% Webster County 2.9%	2.9%	2
42441	Hopkins County 93.0% Webster County 7.0%	7.0%	2
42442	Hopkins County 99.0% Christian County 1.0%	1.0%	2
42445	Caldwell County 91.1% Lyon County 4.6% Hopkins County 4.1% Trigg County 0.2%	8.9%	4
42450	Webster County 50.4% Hopkins County 31.0% Crittenden County 18.6%	49.6%	3
42452	Henderson County 91.7% Webster County 8.3%	8.3%	2
42453	Hopkins County 93.5% Christian County 6.5%	6.5%	2
42456	Webster County 63.5% Hopkins County 36.5%	36.5%	2
42459	Union County 82.4% Crittenden County 17.6%	17.6%	2
42461	Union County 98.8% Henderson County 1.2%	1.2%	2
42462	Union County 68.0% Henderson County 32.0%	32.0%	2
42464	Hopkins County 71.0% Christian County 15.3% Muhlenberg County 13.7%	29.0%	3
42518	Wayne County 50.3% Pulaski County 49.7%	49.7%	2
42528	Casey County 66.3% Russell County 17.4% Adair County 16.2%	33.6%	3
42539	Casey County 98.9% Adair County 1.1%	1.1%	2
42544	Pulaski County 76.1% Russell County 14.3% Wayne County 9.6%	23.9%	3
42565	Casey County 99.3% Russell County 0.7%	0.7%	2
42567	Pulaski County 87.8% Lincoln County 12.3%	12.3%	2
42602	Clinton County 97.7% Russell County 1.3% Wayne County 0.9% Pickett County, TN 0.2%	2.3%	4
42603	Wayne County 55.0% Clinton County 45.0%	45.0%	2
42642	Russell County 86.0% Adair County 10.3% Pulaski County 3.0% Casey County 0.7%	14.0%	4
42712	Hardin County 52.3% Grayson County 47.7%	47.7%	2
42715	Adair County 61.8% Metcalfe County 22.5% Cumberland County 15.7%	38.2%	3
42716	Larue County 74.7% Green County 15.0% Taylor County 10.2%	25.3%	3
42717	Cumberland County 97.9% Clinton County 2.1%	2.1%	2
42718	Taylor County 74.4% Marion County 13.3% Green County 7.2% Larue County 5.1%	25.6%	4
42721	Grayson County 89.9% Butler County 6.1% Edmonson County 4.0%	10.1%	3
42728	Adair County 96.0% Taylor County 3.9% Metcalfe County under 0.1%	4.0%	3
42729	Hart County 71.3% Edmonson County 28.6%	28.6%	2
42733	Taylor County 70.2% Casey County 27.2% Adair County 2.6%	29.8%	3
42741	Adair County 98.3% Russell County 1.7%	1.7%	2
42743	Green County 97.3% Adair County 2.7%	2.7%	2
42746	Hart County 78.8% Green County 15.2% Metcalfe County 6.0%	21.3%	3
42748	Larue County 99.8% Hardin County 0.2%	0.2%	2
42749	Hart County 80.4% Metcalfe County 13.2% Barren County 6.4%	19.6%	3
42754	Grayson County 90.3% Breckinridge County 9.1% Edmonson County 0.6%	9.7%	3
42757	Hart County 63.3% Larue County 29.6% Green County 7.2%	36.7%	3
42764	Green County 87.0% Larue County 13.0%	13.0%	2
42776	Hardin County 69.0% Larue County 31.0%	31.0%	2
42782	Green County 87.2% Hart County 12.8%	12.8%	2
42784	Hart County 39.4% Hardin County 36.4% Larue County 24.2%	60.6%	3

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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