San Marcos is a city of about 70,000 in Hays County, positioned along I-35 roughly midway between Austin and San Antonio. Texas State University, with over 38,000 students, is the city's dominant institution and largest employer, giving San Marcos a youthful, energetic character. The San Marcos River — one of the most beautiful spring-fed rivers in Texas — runs through the city and supports a tubing and recreation culture that rivals New Braunfels' Comal and Guadalupe rivers. The San Marcos and Tanger Premium Outlets draw shoppers from across central Texas and are major sales-tax generators for the city. Beyond the university, employers include the outlet malls, Hays CISD (which serves much of the surrounding area), and a growing number of businesses attracted to the I-35 growth corridor. Neighborhoods range from older homes and student housing near the Texas State campus to newer master-planned communities on the west side and along the Highway 123 corridor. The cost of living has risen alongside Austin's boom, as San Marcos captures overflow demand from the capital. The city has invested in its downtown square, which features restaurants, shops, and the historic courthouse. Flash flooding is a serious concern — the Blanco River and San Marcos River can rise dramatically during heavy rain, as demonstrated by the devastating Memorial Day 2015 floods. Hays County is one of the fastest-growing counties in the nation.