The San Marcos River, originating from natural springs in the town of San Marcos, Texas, is considered one of the most biologically diverse aquatic ecosystems in the southwestern United States. This crystal-clear, spring-fed waterway maintains a constant, refreshing 72-degree temperature year-round, making it an excellent fishing destination regardless of season. The river's constant flows, even during drought periods, combined with its diverse underwater structure including tree-lined banks, shady canopies, and varied habitat, creates an exceptional fishing environment. The headwaters bubble up from San Marcos Springs in the heart of San Marcos and the Texas State University campus, providing the beginning of this pristine ecosystem that supports a rich variety of fish species.