San Augustine County is a county located in the U.S. state of Texas. As of the 2010 census, its population was 8,865. Its county seat is San Augustine.HistorySan Augustine County was formed in 1837. It was supposedly named after the Saint, Augustine of Hippo. However, it seems plausible that the county was named for the town of San Augustine, which had been established five years earlier and whose name was based upon an 18th-century Spanish presidio (fortress).GeographyAccording to the U.S. Census Bureau, the county has a total area of, of which is land and (10%) is water.Major highways20px U.S. Highway 9620px State Highway 2120px State Highway 10320px State Highway 147Adjacent countiesShelby County (north)Sabine County (east)Jasper County (south)Angelina County (southwest)Nacogdoches County (west)