Alamosa County, Colorado
County seat: Alamosa · Population 16,688 (2025) · 723 sq mi
Alamosa County is the 30th most populous of Colorado's 64 counties, with 16,688 people (2025 estimate). Its county seat is Alamosa. It is part of the Region 8: San Luis Valley region, one of the 14 Planning and Management Regions of Colorado. The map shows its 2 cities and towns and the 5 neighboring counties.
Alamosa County facts
- County seat
- Alamosa
- Population (2025 estimate)
- 16,688 +1.9% since 2020
- Land area
- 723 sq mi 53rd largest of 64
- Water area
- 1 sq mi
- Population density
- 23 per sq mi
- Established
- 1913
- Largest city
- Alamosa 9,849
- Median household income
- $55,397
- Cities and towns
- 2 plus 1 CDPs
- ZIP codes
- 5
- Time zone
- Mountain
- FIPS code
- 08003
Cities and towns in Alamosa County
Alamosa County has 2 incorporated cities, towns and villages. Populations count the people living inside Alamosa County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Alamosa (county seat) | City | 9,849 | |
| Hooper | Town | 77 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Alamosa East | 1,298 |
ZIP codes in Alamosa County
5 ZIP codes reach into Alamosa County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 81101 also Conejos County
- 81125 also Saguache and Rio Grande counties
- 81136 also Saguache County
- 81144 also Rio Grande County
- 81146
Population of Alamosa County, 2020–2025
Alamosa County grew by 310 people (+1.9%) between April 2020 and July 2025: 40 more births than deaths and a net gain of 274 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 16,377 |
| 2021 | 16,584 |
| 2022 | 16,630 |
| 2023 | 16,695 |
| 2024 | 16,691 |
| 2025 | 16,688 |
Neighboring counties
- Saguache County northwest · 6,732 people
- Rio Grande County west · 11,087 people
- Costilla County southeast · 3,679 people
- Conejos County southwest · 7,529 people
- Huerfano County east · 7,011 people
Printable Alamosa County map
The PDF is a vector file with real text: it prints sharp on Letter paper and you can search it for a town. The PNG is 2400 pixels wide for slides and documents. Both are free to use with a credit to WhichCounty.
- PDF (Letter) (61 KB)
- PNG (2400 px) (56 KB)
Paste this code to embed the map on your site:
Sources
- Boundaries: U.S. Census Bureau, 2025 Cartographic Boundary Files (1:500,000).
- Population: Census Bureau county and city estimates, Vintage 2025. CDP populations: American Community Survey 2020–2024.
- Places and ZIP codes: Census Bureau 2026 Gazetteer and 2020 ZIP Code Tabulation Area relationship files.
- County seat, founding year and name origin: Wikidata (CC0), checked against state sources.
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