The Annual San Marcos River Clean Up is a litter pickup event aimed to help beautify the river, creeks, and river banks throughout San Marcos, Texas.

Every Spring on the first Saturday in March, folks from all over Texas participate in the world's longest river clean up. Help us pick up trash along the entire length of the San Marcos River (approximately 90 miles). This group will mainly focus on beautifying the upper San Marcos River and it's banks. If you have any questions about canoeing or cleaning the lower part of the river, please visit http://www.txrivers.org/calendar.html.