The San Marcos founding site functioned first as a natural resource hub, anchored by San Marcos Springs, whose reliable flow made the location attractive for settlement, milling, and later recreation. Anglo-American settlement began in earnest in 1846, and by 1848, when Hays County was organized, the community served as the new county seat. In its early decades San Marcos operated primarily as a mill town and agricultural processing center, using the power of the San Marcos River to grind grain and gin cotton for surrounding farms, while also functioning as a stop in the regional cart trade linking inland farmers with coastal markets; the arrival of the railroad in 1880 reinforced this commercial and shipping role. Beginning in 1899, with the chartering of Southwest Texas State Normal School (opened 1903), San Marcos took on a new civic function as an educational center, a role that expanded steadily as the institution grew into Texas State University and became the city's largest employer. The springs themselves also came to function as a recreational and tourism attraction, drawing visitors to attractions such as Aquarena Springs. Today San Marcos functions as a mid-sized Texas city combining these historic roles: a college town built around Texas State University, a regional commercial and manufacturing center benefiting from its location between Austin and San Antonio, and a tourism destination centered on its springs and river.