County outline
Where San Augustine County is located
Area breakdown
Land accounts for 89.6% of San Augustine County’s measured area and water for 10.4%. Its combined area converts to 1,534 square kilometers or approximately 379,071 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 530.659 | 1,374.401 | 339,621.8 |
| Water | 61.639 | 159.644 | 39,449 |
| Total | 592.298 | 1,534.045 | 379,070.7 |
How San Augustine County compares
By original Census land area, San Augustine County ranks #236 of 254 in Texas and #1976 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.584 times the Texas county-equivalent median of 908.7 square miles. It accounts for 0.2% of the combined county land area in the state.
See the complete Texas ranking · What counts as a county equivalent?
Population and density of San Augustine County
The Census Bureau estimates that 7,722 people lived in San Augustine County on July 1, 2025. That ranks #2,670 of 3,222 county equivalents nationally and #178 of 254 in Texas. Since the April 1, 2020 estimates base of 7,921, the population has declined by 199 (−2.5%), compared with +8.8% for Texas as a whole.
With 530.7 square miles of land, that is 15 people per square mile (5.6 per km²), placing San Augustine County #2,488 nationally for density and #152 in Texas. The median county equivalent has 47 people per square mile; the Texas median is 22. Put another way, there are about 44 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 7,923 | 7,908 | 7,880 | 7,865 | 7,777 | 7,722 |
| Change | — | −15 | −28 | −15 | −88 | −55 |
U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.
Cities and towns in San Augustine County
2 incorporated places lie at least partly in San Augustine County. Together they are home to 2,017 people (26.1%); the other 5,705 (73.9%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is San Augustine city, with 1,839 residents in the county.
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| San Augustine cityCounty seat | 1,839 | −3.9% | 4.717 |
| Broaddus town | 178 | −4.3% | 0.373 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside San Augustine County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
Metropolitan area
San Augustine County is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.
ZIP codes
4 ZIP Code Tabulation Areas have land in San Augustine County; 3 of them have most of their land inside the county, and the others mainly cover neighboring areas.
75929759307593575972
ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.
Counties bordering San Augustine County
San Augustine County shares a land border with 5 county equivalents. It has more land than 1 of them. The largest neighbor is Nacogdoches County (946.3 mi²) and the smallest is Sabine County (491.7 mi²). Together with its neighbors, San Augustine County forms a block of 4,500.8 mi² of land, of which it holds 11.8%.
| Bordering county equivalent | Land mi² | Size vs. San Augustine | Compare |
|---|---|---|---|
| Nacogdoches County | 946.3 | 1.8× larger | Compare |
| Jasper County | 938.7 | 1.8× larger | Compare |
| Angelina County | 797.9 | 1.5× larger | Compare |
| Shelby County | 795.6 | 1.5× larger | Compare |
| Sabine County | 491.7 | 1.1× smaller | Compare |
How big is San Augustine County compared with U.S. states?
San Augustine County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.9 times as much. Texas’s county land could hold about 492 areas the size of San Augustine County.
Another way to picture it: the same land area would fill a square about 23 miles (37.1 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.
State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.
What stands out about San Augustine County?
San Augustine County has more land than 1,246 of the other 3,221 county equivalents in the dataset.
A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.
Does including water change its rank?
Using land plus water places San Augustine County at #1,770 nationally by total area, 206 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.
Its water share is 10.4%, compared with a national county-equivalent median of 1.2% — 9.2 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.
Closest positions in the national land ranking
These entries sit immediately beside San Augustine County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1975 | Humphreys County, Tennessee | 530.8 | Compare |
| #1976 | San Augustine County, Texas | 530.7 | This county |
| #1977 | Brown County, Wisconsin | 530.1 | Compare |
Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.
Representative coordinates
The Census internal point is 31.382449, -94.163180. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.
Source and precision
U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,374,400,349 m²; AWATER: 159,644,686 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How big is San Augustine County?
San Augustine County, Texas has 530.7 square miles (1,374.4 km²) of land and 61.6 square miles of water, for a total area of 592.3 square miles. It ranks #1976 of 3,222 U.S. county equivalents by land area.
Is San Augustine County the largest county in Texas?
No. San Augustine County ranks #236 of 254 in Texas by land area. The largest is Brewster County, with 6,183.8 square miles of land.
What counties border San Augustine County?
San Augustine County shares a land border with Nacogdoches County, Sabine County, Shelby County, Angelina County, and Jasper County.
What is the population of San Augustine County?
The Census Bureau estimates San Augustine County had 7,722 residents on July 1, 2025, ranking #2,670 of 3,222 county equivalents. That is 15 people per square mile of land.
What is the county seat of San Augustine County?
The county seat of San Augustine County is San Augustine.
What cities and towns are in San Augustine County?
San Augustine County has 2 incorporated places. The most populous are San Augustine city and Broaddus town; 5,705 residents live outside any incorporated place.
Is San Augustine County part of a metropolitan area?
No. San Augustine County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.
How many ZIP codes are in San Augustine County?
4 ZIP Code Tabulation Areas have land in San Augustine County, and 3 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does San Augustine County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.9 times as much land.
How many acres of land are in San Augustine County?
The land measurement converts to approximately 339,622 acres. Including water, total area is approximately 379,071 acres. One square mile equals 640 acres.
Why might another source show a different area?
Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.
Can this establish a property boundary?
No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.