ZIP codes and county lines in New Mexico

82 of the 379 ZIP code areas in New Mexico, or 21.6%, 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: 379
In more than one county: 82
At least 5% in a second county: 67
Cross a state line: 10

How New Mexico compares

New Mexico ranks 30 of 52 (the 50 states, DC and Puerto Rico) by the share of its ZIP code areas that overlap more than one county. 32 of its counties have at least one split ZIP code area along an edge. 10 of its ZIP code areas also reach into Arizona, Colorado, Texas and Utah, so a ZIP list that is meant to stop at the state line does not.

Counties with the most split ZIP code areas

Rio Arriba County: 13 ZIP codes shared with another county
McKinley County: 11 ZIP codes shared with another county
San Miguel County: 11 ZIP codes shared with another county
Sandoval County: 8 ZIP codes shared with another county
San Juan County: 8 ZIP codes shared with another county

Every split ZIP code area in New Mexico

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
79835	El Paso County, TX 98.8% Doña Ana County 1.2%	1.2%	2
79837	Otero County 81.7% Hudspeth County, TX 18.3%	18.3%	2
79922	El Paso County, TX 82.9% Doña Ana County 17.1%	17.1%	2
81120	Conejos County, CO 92.1% Rio Arriba County 7.9%	7.9%	2
81137	La Plata County, CO 79.6% San Juan County 17.3% Archuleta County, CO 3.1%	20.4%	3
86504	Apache County, AZ 98.8% McKinley County 1.3%	1.3%	2
86514	Apache County, AZ 84.0% San Juan County, UT 15.1% San Juan County 1.0%	16.1%	3
86515	McKinley County 88.2% Apache County, AZ 11.8%	11.8%	2
87002	Valencia County 99.8% Socorro County 0.2%	0.2%	2
87006	Socorro County 95.8% Valencia County 4.2%	4.2%	2
87011	Socorro County 72.3% Lincoln County 27.7%	27.7%	2
87013	Sandoval County 55.1% McKinley County 44.4% Rio Arriba County 0.5%	44.9%	3
87015	Santa Fe County 62.0% Torrance County 20.5% Bernalillo County 17.5%	38.0%	3
87018	Sandoval County 97.6% Rio Arriba County 2.4%	2.4%	2
87020	Cibola County 86.6% McKinley County 13.4%	13.4%	2
87026	Cibola County 49.5% Valencia County 28.5% Bernalillo County 22.0%	50.5%	3
87035	Torrance County 96.9% Santa Fe County 3.1%	3.1%	2
87036	Torrance County 62.4% Socorro County 37.6%	37.6%	2
87037	San Juan County 96.7% Rio Arriba County 3.3%	3.3%	2
87045	McKinley County 98.3% Cibola County 1.7%	1.7%	2
87046	Rio Arriba County 78.4% Sandoval County 21.6%	21.6%	2
87047	Sandoval County 41.5% Santa Fe County 29.8% Bernalillo County 28.7%	58.5%	3
87048	Sandoval County 98.1% Bernalillo County 1.9%	1.9%	2
87056	Santa Fe County 86.4% San Miguel County 13.6%	13.6%	2
87062	Socorro County 99.4% Valencia County 0.6%	0.6%	2
87068	Bernalillo County 53.7% Valencia County 46.3%	46.3%	2
87122	Bernalillo County 97.3% Sandoval County 2.7%	2.7%	2
87124	Sandoval County 100.0% Bernalillo County under 0.1%	under 0.1%	2
87313	McKinley County 89.0% San Juan County 11.1%	11.1%	2
87321	Cibola County 70.3% McKinley County 29.7%	29.7%	2
87323	McKinley County 85.6% Cibola County 14.4%	14.4%	2
87325	McKinley County 61.5% San Juan County 38.5%	38.5%	2
87327	McKinley County 86.0% Cibola County 14.0%	14.0%	2
87328	Apache County, AZ 38.8% McKinley County 31.5% San Juan County 29.7%	61.2%	3
87412	Rio Arriba County 72.2% San Juan County 27.8%	27.8%	2
87419	San Juan County 53.8% Rio Arriba County 46.2%	46.2%	2
87521	Rio Arriba County 66.5% Taos County 33.5%	33.5%	2
87522	Santa Fe County 78.9% Rio Arriba County 21.1%	21.1%	2
87531	Taos County 59.0% Rio Arriba County 41.0%	41.0%	2
87532	Rio Arriba County 75.0% Santa Fe County 24.9%	24.9%	2
87535	Santa Fe County 92.7% San Miguel County 7.3%	7.3%	2
87544	Sandoval County 57.6% Los Alamos County 42.4%	42.4%	2
87549	Rio Arriba County 85.0% Taos County 15.0%	15.0%	2
87573	San Miguel County 59.0% Santa Fe County 41.0%	41.0%	2
87577	Rio Arriba County 51.3% Taos County 48.8%	48.8%	2
87711	San Miguel County 75.3% Guadalupe County 24.7%	24.7%	2
87742	San Miguel County 58.2% Mora County 41.8%	41.8%	2
87745	San Miguel County 90.4% Mora County 9.6%	9.6%	2
87746	San Miguel County 94.3% Harding County 5.7%	5.7%	2
87825	Socorro County 67.5% Catron County 32.5%	32.5%	2
87936	Doña Ana County 86.7% Sierra County 13.3%	13.3%	2
87943	Sierra County 45.3% Socorro County 37.1% Catron County 17.6%	54.7%	3
88034	Grant County 95.5% Luna County 4.5%	4.5%	2
88040	Hidalgo County 86.3% Grant County 13.7%	13.7%	2
88045	Hidalgo County 77.3% Grant County 22.7%	22.7%	2
88081	Otero County 89.7% Doña Ana County 10.3%	10.3%	2
88101	Curry County 98.9% Roosevelt County 1.1%	1.1%	2
88112	Curry County 66.3% Quay County 33.8%	33.8%	2
88116	Roosevelt County 51.2% Chaves County 48.8%	48.8%	2
88118	Roosevelt County 82.6% Curry County 17.4%	17.4%	2
88120	Quay County 71.5% Curry County 28.5%	28.5%	2
88124	Curry County 58.2% Roosevelt County 27.8% Quay County 14.0%	41.8%	3
88134	De Baca County 83.8% Roosevelt County 16.2%	16.2%	2
88135	Curry County 93.5% Roosevelt County 6.5%	6.5%	2
88136	De Baca County 66.9% Lincoln County 33.1%	33.1%	2
88201	Chaves County 86.6% Lincoln County 13.4%	13.4%	2
88250	Chaves County 65.8% Eddy County 34.2%	34.2%	2
88253	Chaves County 74.0% Eddy County 26.0%	26.0%	2
88301	Lincoln County 97.7% Socorro County 2.3%	2.3%	2
88318	Lincoln County 69.9% Torrance County 30.1%	30.1%	2
88321	Torrance County 87.9% Guadalupe County 9.5% San Miguel County 2.6%	12.1%	3
88339	Chaves County 59.4% Otero County 40.6%	40.6%	2
88344	Otero County 69.8% Chaves County 30.2%	30.2%	2
88401	Quay County 90.2% San Miguel County 9.8%	9.8%	2
88410	Union County 61.4% Harding County 38.6%	38.6%	2
88414	Colfax County 67.1% Union County 32.9%	32.9%	2
88415	Union County 84.2% Harding County 15.8%	15.8%	2
88417	Guadalupe County 81.5% Quay County 18.6%	18.6%	2
88422	Union County 64.5% Colfax County 35.5%	35.5%	2
88426	Harding County 65.7% Quay County 31.2% San Miguel County 3.1%	34.3%	3
88430	Quay County 72.0% Union County 25.4% Oldham County, TX 2.6%	28.0%	3
88431	Guadalupe County 57.6% San Miguel County 42.4%	42.4%	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

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