San Marcos River

San Marcos River
Texas
The San Marcos River downstream from the San Marcos Springs
Country	United States
State	Texas
Source	San Marcos Springs
- location	San Marcos, Texas, U.S.A
- elevation	575 ft (175 m)
Mouth	Guadalupe River
- location	Gonzales County, Texas, U.S.A
Length	75 mi (121 km)
Basin	522 sq mi (1,352 km2)
Discharge
- average	236 cu ft/s (7 m3/s)
Map of the San Marcos River

The San Marcos River rises from the San Marcos Springs, the location of Aquarena Springs, in San Marcos, Texas. The springs are home to several threatened or endangered species, including the Texas Blind Salamander, Fountain Darter, and Texas Wild Rice. The river is a popular recreational area, and is frequented for tubing, canoeing, swimming, and fishing.

The river begins at San Marcos Springs, rising from the Edwards Aquifer into Spring Lake. Access to much of the headwaters is restricted because of the delicate ecosystem and numerous rare species. The upper river flows through Texas State University and San Marcos, and is a popular recreational area. It is joined by the Blanco River after four miles, passes through Luling and Palmetto State Park. Near Gonzales it flows into the Guadalupe River after a total of 75 miles (121 km). This course is the first section of the Texas Water Safari.

The history and naming of the river is somewhat unclear. It may have been discovered by Alonso de León's expedition in 1689, but some scholars believe they instead had found the Colorado or Navidad rivers. The convention came to call the first sizable river beyond the Guadalupe. However, at the time, the Comal River was often called the Guadalupe, and part of the Guadalupe often called San Ybón. In 1808, the Spanish established San Marcos de Neve, just south of present-day San Marcos. They had friendly relations with the Tonkawa Indians, but the hostile Comanche tribe forced them to leave in 1812. In 1998 and 2015, the river was affected by severe flooding.