ZIP codes and county lines in California

175 of the 1808 ZIP code areas in California, or 9.7%, 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: 1,808
In more than one county: 175
At least 5% in a second county: 123
Cross a state line: 6

How California compares

California ranks 44 of 52 (the 50 states, DC and Puerto Rico) by the share of its ZIP code areas that overlap more than one county. 57 of its counties have at least one split ZIP code area along an edge. 6 of its ZIP code areas also reach into Nevada and Oregon, so a ZIP list that is meant to stop at the state line does not.

Counties with the most split ZIP code areas

Los Angeles County: 19 ZIP codes shared with another county
San Bernardino County: 14 ZIP codes shared with another county
Fresno County: 13 ZIP codes shared with another county
Alameda County: 12 ZIP codes shared with another county
Riverside County: 12 ZIP codes shared with another county

Every split ZIP code area in California

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
89010	Esmeralda County, NV 90.3% Mineral County, NV 6.0% Mono County 3.8%	9.8%	3
89019	Clark County, NV 77.6% San Bernardino County 21.5% Inyo County 0.9%	22.4%	3
89060	Nye County, NV 98.1% Inyo County 1.9%	1.9%	2
89061	Nye County, NV 95.6% Inyo County 4.4%	4.4%	2
89439	Washoe County, NV 74.3% Sierra County 25.7%	25.7%	2
90265	Los Angeles County 68.6% Ventura County 31.4%	31.4%	2
90623	Orange County 98.0% Los Angeles County 2.0%	2.0%	2
90630	Orange County 99.5% Los Angeles County 0.6%	0.6%	2
90631	Orange County 54.3% Los Angeles County 45.7%	45.7%	2
90638	Los Angeles County 99.1% Orange County 0.9%	0.9%	2
90716	Los Angeles County 99.8% Orange County 0.2%	0.2%	2
90740	Orange County 99.9% Los Angeles County 0.1%	0.1%	2
91304	Los Angeles County 86.1% Ventura County 13.9%	13.9%	2
91307	Los Angeles County 55.2% Ventura County 44.8%	44.8%	2
91311	Los Angeles County 96.7% Ventura County 3.3%	3.3%	2
91361	Ventura County 82.7% Los Angeles County 17.3%	17.3%	2
91362	Ventura County 94.5% Los Angeles County 5.5%	5.5%	2
91709	San Bernardino County 99.7% Los Angeles County 0.3%	0.3%	2
91759	Los Angeles County 79.3% San Bernardino County 20.7%	20.7%	2
91766	Los Angeles County 95.9% San Bernardino County 4.1%	4.1%	2
92004	San Diego County 58.0% Imperial County 42.0%	42.0%	2
92028	San Diego County 99.3% Riverside County 0.7%	0.7%	2
92225	Riverside County 99.5% Imperial County 0.5%	0.5%	2
92274	Riverside County 66.1% Imperial County 33.9%	33.9%	2
92277	San Bernardino County 78.0% Riverside County 22.0%	22.0%	2
92320	Riverside County 100.0% San Bernardino County under 0.1%	under 0.1%	2
92324	San Bernardino County 67.6% Riverside County 32.4%	32.4%	2
92373	San Bernardino County 58.3% Riverside County 41.7%	41.7%	2
92397	Los Angeles County 66.3% San Bernardino County 33.7%	33.7%	2
92399	San Bernardino County 99.0% Riverside County 1.0%	1.0%	2
92509	Riverside County 99.4% San Bernardino County 0.6%	0.6%	2
92530	Riverside County 94.4% Orange County 5.6%	5.6%	2
92562	Riverside County 81.5% San Diego County 18.6%	18.6%	2
92672	San Diego County 76.4% Orange County 23.6%	23.6%	2
92880	Riverside County 92.7% San Bernardino County 7.3%	7.3%	2
93013	Santa Barbara County 74.7% Ventura County 25.3%	25.3%	2
93201	Tulare County 85.7% Kings County 14.3%	14.3%	2
93210	Fresno County 90.3% Monterey County 6.4% San Benito County 3.4%	9.7%	3
93212	Kings County 60.7% Tulare County 39.3%	39.3%	2
93215	Kern County 59.5% Tulare County 40.5%	40.5%	2
93225	Ventura County 63.9% Kern County 36.1%	36.1%	2
93230	Kings County 99.6% Tulare County 0.4%	0.4%	2
93238	Tulare County 66.5% Kern County 33.5%	33.5%	2
93242	Fresno County 83.0% Kings County 17.0%	17.0%	2
93243	Kern County 63.8% Los Angeles County 36.2%	36.2%	2
93252	Ventura County 66.5% Kern County 18.2% Santa Barbara County 9.2% San Luis Obispo County 6.2%	33.5%	4
93254	Santa Barbara County 91.6% San Luis Obispo County 8.4%	8.4%	2
93274	Tulare County 95.4% Kings County 4.6%	4.6%	2
93426	Monterey County 82.4% San Luis Obispo County 17.6%	17.6%	2
93434	Santa Barbara County 99.3% San Luis Obispo County 0.7%	0.7%	2
93451	Monterey County 84.8% San Luis Obispo County 15.2%	15.2%	2
93454	Santa Barbara County 72.1% San Luis Obispo County 27.9%	27.9%	2
93458	Santa Barbara County 99.8% San Luis Obispo County 0.1%	0.1%	2
93461	San Luis Obispo County 90.8% Kern County 9.2%	9.2%	2
93514	Mono County 56.4% Inyo County 43.6%	43.6%	2
93516	Kern County 52.0% San Bernardino County 48.0%	48.0%	2
93527	Tulare County 50.7% Kern County 34.8% Inyo County 14.5%	49.3%	3
93536	Los Angeles County 94.8% Kern County 5.2%	5.2%	2
93555	Kern County 92.0% San Bernardino County 8.1%	8.1%	2
93560	Kern County 95.2% Los Angeles County 4.8%	4.8%	2
93601	Madera County 63.8% Mariposa County 36.2%	36.2%	2
93602	Fresno County 95.8% Madera County 4.2%	4.2%	2
93610	Madera County 85.1% Merced County 14.9%	14.9%	2
93618	Tulare County 89.0% Fresno County 11.0%	11.0%	2
93620	Merced County 75.6% Fresno County 24.1% Madera County 0.3%	24.4%	3
93622	Fresno County 83.5% Madera County 10.2% Merced County 6.3%	16.5%	3
93623	Mariposa County 96.0% Madera County 4.0%	4.0%	2
93626	Madera County 74.3% Fresno County 25.7%	25.7%	2
93631	Tulare County 53.2% Fresno County 26.1% Kings County 20.8%	46.8%	3
93641	Fresno County 71.5% Tulare County 28.5%	28.5%	2
93646	Tulare County 58.3% Fresno County 41.7%	41.7%	2
93653	Madera County 69.1% Mariposa County 30.9%	30.9%	2
93654	Fresno County 90.9% Tulare County 9.1%	9.1%	2
93656	Fresno County 90.7% Kings County 9.3%	9.3%	2
93720	Fresno County 97.7% Madera County 2.3%	2.3%	2
93930	Monterey County 80.8% San Benito County 19.2%	19.2%	2
94028	San Mateo County 81.1% Santa Clara County 18.9%	18.9%	2
94303	Santa Clara County 67.1% San Mateo County 32.9%	32.9%	2
94501	Alameda County 99.4% San Francisco County 0.6%	0.6%	2
94503	Napa County 66.4% Solano County 33.6%	33.6%	2
94505	Contra Costa County 96.0% Alameda County 3.9% San Joaquin County 0.1%	4.0%	3
94514	Contra Costa County 82.5% Alameda County 17.5%	17.5%	2
94515	Sonoma County 50.6% Napa County 49.4%	49.4%	2
94550	Alameda County 61.2% Santa Clara County 38.8%	38.8%	2
94551	Alameda County 63.0% Contra Costa County 37.0%	37.0%	2
94571	Solano County 81.9% Sacramento County 18.1%	18.1%	2
94574	Napa County 98.7% Sonoma County 1.3%	1.3%	2
94588	Alameda County 50.9% Contra Costa County 49.1%	49.1%	2
94591	Solano County 97.0% Napa County 3.0%	3.0%	2
94611	Alameda County 95.0% Contra Costa County 5.0%	5.0%	2
94706	Alameda County 99.7% Contra Costa County 0.3%	0.3%	2
94707	Alameda County 64.8% Contra Costa County 35.2%	35.2%	2
94708	Contra Costa County 58.4% Alameda County 41.6%	41.6%	2
94920	Marin County 99.9% San Francisco County 0.1%	0.1%	2
94952	Marin County 51.5% Sonoma County 48.5%	48.5%	2
95004	Monterey County 56.4% San Benito County 43.6%	43.6%	2
95023	San Benito County 63.5% Santa Clara County 36.5%	36.5%	2
95033	Santa Cruz County 52.6% Santa Clara County 47.4%	47.4%	2
95076	Santa Cruz County 74.5% Monterey County 22.7% Santa Clara County 2.9%	25.5%	3
95219	San Joaquin County 83.6% Contra Costa County 16.4%	16.4%	2
95223	Alpine County 80.9% Calaveras County 17.3% Tuolumne County 1.8%	19.1%	3
95230	Stanislaus County 49.0% Calaveras County 29.3% San Joaquin County 21.6%	51.0%	3
95236	San Joaquin County 98.1% Calaveras County 1.9%	1.9%	2
95304	San Joaquin County 100.0% Stanislaus County under 0.1%	under 0.1%	2
95311	Mariposa County 97.8% Tuolumne County 2.1%	2.1%	2
95316	Stanislaus County 76.8% Merced County 23.2%	23.2%	2
95321	Tuolumne County 98.0% Mariposa County 2.0%	2.0%	2
95322	Merced County 97.7% Stanislaus County 2.3%	2.3%	2
95329	Tuolumne County 45.4% Stanislaus County 36.9% Mariposa County 17.7%	54.6%	3
95360	Stanislaus County 76.5% Merced County 23.5%	23.5%	2
95361	Stanislaus County 97.7% San Joaquin County 2.3%	2.3%	2
95369	Merced County 86.4% Mariposa County 13.6%	13.6%	2
95377	San Joaquin County 89.3% Alameda County 10.7%	10.7%	2
95380	Stanislaus County 75.3% Merced County 24.7%	24.7%	2
95385	Stanislaus County 98.0% San Joaquin County 2.0%	2.0%	2
95389	Mariposa County 81.9% Tuolumne County 18.1%	18.1%	2
95391	Alameda County 69.5% San Joaquin County 30.5%	30.5%	2
95425	Sonoma County 67.5% Mendocino County 32.5%	32.5%	2
95469	Mendocino County 63.1% Lake County 36.9%	36.9%	2
95476	Sonoma County 97.8% Napa County 2.1%	2.1%	2
95526	Humboldt County 86.0% Trinity County 13.9%	13.9%	2
95542	Humboldt County 97.2% Mendocino County 2.8%	2.8%	2
95552	Trinity County 93.2% Humboldt County 6.8%	6.8%	2
95556	Humboldt County 89.0% Siskiyou County 11.0%	11.0%	2
95589	Humboldt County 78.6% Mendocino County 21.4%	21.4%	2
95602	Placer County 78.9% Nevada County 21.1%	21.1%	2
95603	Placer County 100.0% El Dorado County under 0.1%	under 0.1%	2
95612	Yolo County 88.7% Solano County 11.3%	11.3%	2
95616	Yolo County 96.8% Solano County 3.2%	3.2%	2
95618	Yolo County 77.3% Solano County 22.7%	22.7%	2
95620	Solano County 75.8% Yolo County 24.1%	24.1%	2
95626	Sacramento County 57.5% Placer County 25.6% Sutter County 16.9%	42.5%	3
95629	Amador County 60.8% El Dorado County 39.2%	39.2%	2
95630	Sacramento County 99.9% El Dorado County under 0.1%	under 0.1%	2
95632	Sacramento County 69.4% San Joaquin County 30.6%	30.6%	2
95640	Amador County 99.7% Sacramento County 0.3%	0.3%	2
95641	Sacramento County 96.6% San Joaquin County 3.4%	3.4%	2
95645	Yolo County 39.5% Sutter County 35.5% Colusa County 25.1%	60.5%	3
95646	Alpine County 97.4% Amador County 2.6%	2.6%	2
95668	Sutter County 69.6% Placer County 30.4%	30.4%	2
95678	Placer County 100.0% Sacramento County under 0.1%	under 0.1%	2
95690	Sacramento County 63.7% Solano County 36.3%	36.3%	2
95692	Yuba County 97.7% Sutter County 2.3%	2.3%	2
95694	Yolo County 80.1% Solano County 19.9%	19.9%	2
95728	Placer County 76.7% Nevada County 23.3%	23.3%	2
95837	Sacramento County 91.5% Sutter County 8.5%	8.5%	2
95901	Yuba County 96.9% Butte County 3.1%	3.1%	2
95914	Butte County 88.1% Yuba County 11.9%	11.9%	2
95922	Yuba County 81.8% Sierra County 18.2%	18.2%	2
95930	Butte County 85.0% Yuba County 15.0%	15.0%	2
95941	Butte County 85.3% Yuba County 14.7%	14.7%	2
95948	Butte County 99.8% Sutter County 0.2%	0.2%	2
95957	Sutter County 95.8% Colusa County 4.2%	4.2%	2
95960	Sierra County 39.1% Nevada County 37.0% Yuba County 23.9%	60.9%	3
95963	Glenn County 88.5% Tehama County 11.5%	11.5%	2
95966	Butte County 96.8% Yuba County 3.2%	3.2%	2
95970	Colusa County 50.5% Glenn County 49.5%	49.5%	2
95973	Butte County 61.5% Tehama County 38.5%	38.5%	2
95977	Yuba County 61.2% Nevada County 38.8%	38.8%	2
95981	Plumas County 76.2% Yuba County 23.8%	23.8%	2
96006	Lassen County 63.9% Modoc County 36.1%	36.1%	2
96022	Tehama County 68.8% Shasta County 31.2%	31.2%	2
96025	Siskiyou County 72.2% Shasta County 27.8%	27.8%	2
96056	Lassen County 53.3% Shasta County 32.9% Modoc County 13.8%	46.7%	3
96059	Tehama County 51.8% Shasta County 48.2%	48.2%	2
96075	Tehama County 91.1% Shasta County 8.9%	8.9%	2
96076	Trinity County 38.7% Tehama County 33.7% Shasta County 27.6%	61.3%	3
96105	Plumas County 59.8% Sierra County 26.3% Lassen County 13.9%	40.2%	3
96110	Modoc County 96.2% Lassen County 3.8%	3.8%	2
96118	Sierra County 82.7% Plumas County 17.3%	17.3%	2
96134	Modoc County 65.8% Siskiyou County 34.2%	34.2%	2
96137	Lassen County 59.5% Plumas County 40.5%	40.5%	2
96142	El Dorado County 99.1% Placer County 0.9%	0.9%	2
96161	Nevada County 69.6% Placer County 30.4%	30.4%	2
97635	Modoc County 92.8% Lake County, OR 7.2%	7.2%	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.

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