County · code 35039
Rio Arriba CountyNew Mexico
Rio Arriba County is a county in northern New Mexico with its seat in Tierra Amarilla. The county was established as one of seven original New Mexico counties in 1846 under Kearny's Code of Laws.
- Founded1852
- County seatTierra Amarilla
- Named forRio Grande
- Land area5,861 sq mi + 35 sq mi water
- Population40,363 2020 Census
- Parcels mapped35,029 checked 16 October 2026
Where it is
Rio Arriba on the map of New Mexico
New Mexico has 33 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Founded in 1852
An old deed may name a county that no longer exists, or a boundary that has since moved.
Rio Arriba County was established in 1846 as one of seven original New Mexico counties under Kearny's Code of Laws for occupied Mexican territory, and was named after the Rio Grande. In 1852, Rio Arriba was redefined and gained territory from San Miguel, Santa Ana, Santa Fe, and exchanged with Taos County, at which time it included parts of present Arizona, Nevada, and New Mexico. When Arizona Territory was created in 1863, Rio Arriba lost its western portion, and later lost territory to the creation of San Juan County in 1887.
- 1846Rio Arriba County created Rio Arriba established as one of seven original New Mexico counties under Kearny's Code of Laws for the occupied Mexican territory. No written definitions given for the counties, boundaries were shown on the "Map of New Mexico Territory made by order of Brig. Gen. S. W. Kearny under instructions from Lieut. W. H. Emory, U.S.T.E. by Lieut's S.W. Abert and W.G. Peck, U.S.T.E. 1846-7." Competing claims to the eastern half of New Mexico resulted in an overlap between Rio Arriba and Bexar (Texas). · Kearny's Code 1846, "Courts and Judicial Powers," secs. 5-7/p. 49; Abel, Map #2; Coan, 252; Williams, 108-109
- 1852Gained territory Rio Arriba gained from San Miguel, Santa Ana, Santa Fe and Non-County Area 1, and exchanged with Taos when all counties redefined; included parts of present Arizona, Nevada and New Mexico. · N.M. Terr. Laws 1851, 1st assy., 2d sess. /p. 291
- 1863Lost territory Rio Arriba lost to creation of Arizona Territory. · U.S. Stat., vol. 12, pp. 664-665; Van Zandt, 165
- 1871Gained territory Rio Arriba gained from Santa Fe when the law of 18 January 1869 was repealed. · N.M. Terr. Laws 1869-1870, 19th assy., ch. 13/p.40
- 1880Exchanged territory Rio Arriba exchanged with Taos. · N.M. Terr. Laws 1880, 24th assy., ch. 46/pp. 103-104
Show all 13 changes
- 1846Rio Arriba County created Rio Arriba established as one of seven original New Mexico counties under Kearny's Code of Laws for the occupied Mexican territory. No written definitions given for the counties, boundaries were shown on the "Map of New Mexico Territory made by order of Brig. Gen. S. W. Kearny under instructions from Lieut. W. H. Emory, U.S.T.E. by Lieut's S.W. Abert and W.G. Peck, U.S.T.E. 1846-7." Competing claims to the eastern half of New Mexico resulted in an overlap between Rio Arriba and Bexar (Texas). · Kearny's Code 1846, "Courts and Judicial Powers," secs. 5-7/p. 49; Abel, Map #2; Coan, 252; Williams, 108-109
- 1848Changed Rio Arriba recognized by the General Assembly of the Territory of New Mexico which convened December 1847 prior to formal designation of New Mexico Territory by the United States Congress. · N.M. Terr. Laws 1847, pp. 37-39
- 1852Gained territory Rio Arriba gained from San Miguel, Santa Ana, Santa Fe and Non-County Area 1, and exchanged with Taos when all counties redefined; included parts of present Arizona, Nevada and New Mexico. · N.M. Terr. Laws 1851, 1st assy., 2d sess. /p. 291
- 1863Lost territory Rio Arriba lost to creation of Arizona Territory. · U.S. Stat., vol. 12, pp. 664-665; Van Zandt, 165
- 1869Lost territory Rio Arriba lost to Santa Fe (later repealed). · N.M. Terr. Laws 1868-1869, 18th assy., ch. 11/pp. 36-38
- 1871Gained territory Rio Arriba gained from Santa Fe when the law of 18 January 1869 was repealed. · N.M. Terr. Laws 1869-1870, 19th assy., ch. 13/p.40
- 1880Exchanged territory Rio Arriba exchanged with Taos. · N.M. Terr. Laws 1880, 24th assy., ch. 46/pp. 103-104
- 1887Lost territory Rio Arriba lost to creation of San Juan. · N.M. Terr. Laws 1887, 27th assy., ch. 13/p. 38
- 1889Lost territory Rio Arriba lost to Santa Fe. · N.M. Terr. Laws 1888, 28th assy., ch. 127/pp. 301-302
- 1895Lost territory Rio Arriba lost to Bernalillo. · N.M. Terr. Laws 1895, 31st assy., ch. 10/pp. 41-42
- 1903Gained territory Rio Arriba gained from Santa Fe. · N.M. Terr. Laws 1903, 35th assy., ch. 24/p. 35
- 1905Lost territory Rio Arriba lost small area to Taos. · N.M. Terr. Laws 1905, 36th assy., ch. 11/pp. 39-40
- 1905Gained territory Rio Arriba gained from Sandoval when Sandoval was abolished, then immediately re-created on the same day with slightly different boundaries. Act passed 20 February 1905; took effect 8 May 1905. · N.M. Terr. Laws 1905, 36th assy., ch. 10/pp. 34-39
Land and parcels
What the maps cover in Rio Arriba
Who publishes each layer, how good it is, and when we last checked.
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Parcels Official
Lot lines and tax-map numbers for 35,029 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 13 October 2026 · checked 16 October 2026 -
Address points Missing
No public address points layer found for Rio Arriba County yet.
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Buildings Reference
Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026
- Official
- from the office that keeps the record
- Good enough
- a reliable statewide or national copy
- Fallback
- a guide only; check the official record
- Missing
- nothing public found yet
People and land
Rio Arriba by the Census
Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.
Rules and offices
Who to ask before you build, dig or sell
Official county pages only. We link to them; we do not copy them, because they change.
Inside a city or town, permits usually come from that city rather than the county.
Records
County government
- County government
The official website of Rio Arriba County.
See your own lot on these maps
Open Rio Arriba County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.
Questions
Common questions about Rio Arriba County
- When was Rio Arriba County founded?
- Rio Arriba County was founded in 1852, and named after Rio Grande.
- What is the county seat of Rio Arriba County?
- The county seat of Rio Arriba County is Tierra Amarilla.
- Is there an online parcel map for Rio Arriba County?
- Yes. A public source publishes a parcel map of 35,029 parcels, rated official here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Rio Arriba County's boundary or name changed?
- Rio Arriba County was created in 1846. Since then the Atlas of Historical County Boundaries records 12 later changes, chiefly involving Santa Fe County, Taos County and Santa Fe. County.
- Is my lot in a flood zone?
- We do not have flood maps for Rio Arriba County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby