TX · GEOID 48405

San Augustine County area

San Augustine County, Texas covers 592.3 square miles: 530.7 square miles of land and 61.6 square miles of water.

Official Census measurements2026 Gazetteer · retrieved September 27, 2026
Land area530.7 mi²
Water area61.6 mi²
Total area592.3 mi²
National land rank#1976

County outline

Generalized outline of San Augustine County, Texas
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where San Augustine County is located

San Augustine County highlighted on a map of all U.S. county equivalents. About the maps

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

MeasurementSquare milesSquare kilometersAcres
Land530.6591,374.401339,621.8
Water61.639159.64439,449
Total592.2981,534.045379,070.7

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?

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.

Land area compared with the typical county equivalent
San Augustine County530.7 mi²
Texas median908.7 mi²
National median604.5 mi²

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 rankCounty equivalentLand mi²Comparison
#1975Humphreys County, Tennessee530.8Compare
#1976San Augustine County, Texas530.7This county
#1977Brown County, Wisconsin530.1Compare

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.

Download the official county source ZIP ↗ · Methodology

Common questions

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.

Cite this county

Download the complete CSV or JSON dataset