San Marcos, Texas

San Marcos sits in Hays County, 30 miles south of Austin and 50 miles north of San Antonio, straddling Interstate 35 at the point where the Balcones Escarpment drops from the Edwards Plateau into the Blackland Prairie. The 2020 census recorded a population of 67,553 -- a figure inseparable from Texas State University, which enrolled 44,596 students in Fall 2025. Remove the university and you have a mid-size Texas town. With it, you have a city whose rhythm, economy, and culture are shaped by the academic calendar in ways that touch everything from restaurant hours to river crowding. The defining feature is water. The San Marcos Springs -- the second-largest spring system in Texas by volume (after Comal Springs in New Braunfels) -- discharge from the Edwards Aquifer at the headwaters of the San Marcos River, maintaining a temperature of 72 degrees Fahrenheit regardless of season. That constant temperature, combined with the clarity of the water and the springs' output (historically averaging around 175 cubic feet per second), creates an ecosystem found nowhere else on Earth. Eight threatened and endangered species live in the upper 3.8 miles of the river, including the fountain darter, the Texas blind salamander, the San Marcos salamander, and Texas wild rice -- a plant that exists only in this river and is frequently mistaken for seaweed by tubers who uproot it without knowing what they are touching.

What San Marcos Is Known For

1. The river. Spring-fed, 72 degrees, swimmable year-round. The in-town float from City Park to Rio Vista Park takes 45 minutes to an hour. The downstream float through Martindale takes three to four hours. Both are covered in detail on the river page.

2. Texas State University. Founded in 1899 as Southwest Texas State Normal School. Current enrollment exceeds 44,000. The campus sits directly above Spring Lake, and the university operates the Meadows Center for Water and the Environment, which runs glass-bottom boat tours over the spring openings.

3. The springs themselves. Archaeologists have found evidence of human habitation at Spring Lake dating back more than 12,000 years, making it one of the oldest continuously inhabited sites in North America. The springs were a reliable water source in a semi-arid landscape -- people have been drawn to this exact spot since the end of the last ice age.

4. Live music. Cheatham Street Warehouse, opened in 1974 by Kent Finlay and Jim Cunningham in a railroad-side building, launched the careers of George Strait, Stevie Ray Vaughan, Todd Snider, and James McMurtry. It remains an active venue.

5. Outlet shopping. San Marcos Premium Outlets and Tanger Outlets on I-35 form one of the largest outlet shopping destinations in the state. They draw regional traffic from Austin, San Antonio, and the entire I-35 corridor.

History and Heritage

The area around the springs was inhabited by Tonkawa, Comanche, and earlier peoples for millennia before European contact. Spanish missionaries named the river San Marcos in the early 18th century. Three failed Spanish missions were attempted near the springs between 1755 and 1808, none lasting more than a few years.

Modern San Marcos was founded in 1851 by General Edward Burleson, William Lindsey, and Dr. Eli T. Merriman, who took possession of a 640-acre tract that already had 387 residents. The town became the seat of Hays County. A cotton economy developed in the surrounding bottomlands, and the arrival of the International-Great Northern Railroad in the 1880s connected San Marcos to broader markets.

The establishment of Southwest Texas State Normal School in 1899 set the town's trajectory. The school trained teachers for rural Texas, grew steadily through the 20th century, and became Southwest Texas State University in 1969, then Texas State University-San Marcos in 2003, and finally Texas State University in 2013. Lyndon Baines Johnson graduated from the school in 1930 -- a fact the university notes but does not define itself by.

Growth accelerated after 2000 as Austin's expansion pushed south along I-35. San Marcos was the fastest-growing city in the United States by percentage between 2010 and 2014 (Census Bureau data). The population roughly doubled between 2000 and 2020, from 34,733 to 67,553. That growth brought traffic, housing pressure, and the tension between a college town's character and a commuter suburb's infrastructure demands.

The Land and the Water

The San Marcos River begins at Spring Lake on the Texas State campus and flows southeast for approximately 75 miles before joining the Guadalupe River. The upper 3.8 miles -- from the springs through the city -- constitute critical habitat for the eight endangered and threatened species. Below that stretch, the river widens, slows, and becomes the recreational corridor that draws tubers, kayakers, and swimmers.

The terrain around San Marcos transitions from limestone hills on the west (the edge of the Hill Country) to flat agricultural land on the east (the Blackland Prairie). The city sits at the boundary -- which is why the springs exist. The Balcones Fault Zone forces aquifer water to the surface at this geologic contact point.

Flooding is part of the river's history. The Blanco River, which joins the San Marcos River downstream, produced catastrophic flooding in May 2015 (the Memorial Day flood) that killed 13 people in Wimberley and sent a wall of water into the San Marcos system. The city has since invested in flood warning infrastructure and revised its floodplain maps.

Where to Stay

San Marcos does not have a resort hotel or a boutique inn district. Lodging is functional: chain hotels along I-35 (Holiday Inn Express, Hampton Inn, Embassy Suites) serve the outlet shoppers, university visitors, and business travelers. Vacation rentals exist in the surrounding area but are sparse compared to the Hill Country towns to the west. If you want atmosphere, stay in Wimberley (20 minutes northwest) or New Braunfels (20 minutes south) and drive in. If you want convenience and proximity to the river, the I-35 hotels are fine and priced accordingly -- typically $120-180/night, higher during Texas State move-in weekend and graduation.

Practical Information

Getting there: I-35 runs directly through San Marcos. From Austin, take I-35 South for 30 miles (35-50 minutes depending on traffic). From San Antonio, I-35 North for 50 miles (50-60 minutes). The I-35 corridor through San Marcos is congested during rush hours and university class changes.

Parking: Downtown has metered street parking and a few small lots. During summer weekends, parking near City Park and Rio Vista fills early -- arrive before 11am or expect to walk. The outlet malls have massive lots that are never full except Black Friday.

River access: Lions Club Tube Rental in City Park is the only in-city outfitter. $25/tube with shuttle for all-day use. San Marcos residents float free (first 30 minutes free, tiered pricing after). Bring footwear for the walk back from Rio Vista if you skip the shuttle.

Cell service: Reliable throughout the city and along the river corridor.

Groceries and supplies: H-E-B Plus on Wonderworld Drive is the main grocery. Multiple options along I-35 (Walmart, Target, etc.).

The university calendar matters: When Texas State is in session (late August through mid-May), the city is full -- restaurants are busy, the river has weekday swimmers, and traffic on Aquarena Springs Drive is heavy. When school is out (mid-May through late August), the city empties of students but fills with summer tubers. December through January is the quietest period.

Why San Marcos Matters

San Marcos exists because of water. The springs drew people 12,000 years ago and they draw people now -- the mechanism is the same even if the reasons have shifted from survival to recreation. The city's challenge is managing that draw without destroying the thing that creates it. Eight species that live nowhere else on Earth depend on the same water that 67,000 residents drink, 44,000 students swim in, and hundreds of thousands of annual visitors float on. The container ban, the Rio Vista fencing, the park ambassadors, the habitat conservation plan -- all of it is an attempt to let people enjoy the river without loving it to death. Whether that balance holds as the city continues to grow is the open question. For now, the springs still flow, the water is still 72 degrees, and the river is still the reason anyone is here.

San Marcos, Hays County, Texas. Population 67,553 (2020 census). Elevation 581 ft. On I-35, 30 miles south of Austin.