Cat Spring is an unincorporated community in southern Austin County, Texas, United States. It lies along FM 949 south of the city of Bellville, the county seat of Austin County. Its elevation is 308 feet. Although Cat Spring is unincorporated, it has a post office, with the ZIP code of 78933; the ZCTA for ZIP Code 78933 had a population of 76 at the 2000 census.Cat Spring was founded by immigrants from Oldenburg and Westphalia in 1834 and named for a nearby spring where a puma was killed by one of the German immigrants. The community was the location of Texas' first agricultural society, and was the site of a station on the Missouri-Kansas-Texas Railroad established in the 1890s. The community began to decline after World War II.