The Texas State University major university is located in San Marcos, Texas, midway in between Austin and San Antonio along Interstate 35. It extends 492 acres (1.99 km2), consisting of the original land contributed by the city of Texas State University fees San Marcos including Chautauqua Hill on which Old Main still sits. Other parts of the Texas State home including ranch and also ranch land, property, entertainment areas and business incubators cover more than 5,038 acres (20.39 km2) of additional land.

The Quad is the heart of campus due to the fact that it is surrounded by a bulk of the scholastic structures and is near the bus loophole where most of the university bus courses stop on school. The eastern end of the Quad increases to the top of the greatest hill on school where the University's oldest building, Old Main, rests.

The major campus in San Marcos served as the place of the imaginary college TMU (Texas Methodist University) in the NBC TELEVISION series Friday Night Lights.

Old Main

Constructed in 1903 and originally called the Main Building, Old Main was the very first structure on the university. Fourteen years later on, E. Northcraft, the engineer for the structure at Sam Houston, looked after building and construction of the Texas State University Main Building, a red-gabled Victorian Gothic structure.