San Marcos is the county seat of Hays County, situated on the Balcones Escarpment where the Edwards Plateau meets the Blackland Prairie, roughly midway between Austin and San Antonio along Interstate 35. With about 80,000 residents, it is one of the fastest-growing cities on the Austin-San Antonio corridor, anchored by Texas State University and the spring-fed San Marcos River that runs through the heart of town. The river defines the city. Spring Lake, at the headwaters, feeds the San Marcos River with constant-temperature spring water, creating one of Texas's largest spring systems and supporting rare, endangered species and a site of human habitation stretching back more than 10,000 years. Tubing, kayaking, paddleboarding, and swimming on the river are woven into local life, and the university's graduation tradition of jumping into the river underscores its central role. Texas State University, with its hilltop campus and tens of thousands of students, drives much of the city's economy and culture, adding lectures, athletics, and a lively music scene. San Marcos is also a major retail destination: the San Marcos Premium Outlets and Tanger Outlets draw shoppers from across the region at the Exit 200 interchange. Downtown, a historic courthouse square anchors restaurants, bars, and live-music venues, while the city's mermaid heritage and public art give it a distinctive local identity. San Marcos sits between two major metros, roughly 30 miles from both downtown Austin and downtown San Antonio, making it a practical base for commuters to either city. It suits students and university staff, young professionals, and families drawn to river recreation, Hill Country access, and a fast-growing but still approachable Texas community. Its growth has brought new subdivisions and schools alongside the older neighborhoods that ring the university and downtown.