San Marcos River
Hays Co. · 75 mi · Class I–II
72.6CFS/ 3.63 ft
Flood
→Stable
Optimal: 100–400 CFS · USGS #08170500
⚡Flow data is live from USGS·Rapid classifications and CFS ranges need community verification·Know this river?
75 mi
Length
Class I–II
Difficulty
100–400 cfs
Optimal
180 cfs
Avg Flow
162 cfs
Hist. Median
#08170500
USGS Gauge
San Marcos River Foundation · Texas Paddling Trail

Spring-fed and crystal clear, the San Marcos emerges from the Edwards Aquifer at a constant 72 degrees. Glass-bottom boats have showcased the headsprings since the 1940s, and the river through San Marcos is one of the most accessible paddles in the Texas Hill Country.

Trip sections
Spring Lake to Rio Vista Park — 3 mi, crystal spring run through town
Rio Vista to Luling — 40 mi, rural Hill Country paddling
Outfitters
TG Canoes
San Marcos River kayak and canoe rentals
72-Hour Flow Forecast
NOAA NWPS
Loading forecast...
10-Year Flow Patterns
See 10 years of flow patterns for this river — historical analysis is a Pro feature.Upgrade to Pro →
Your Optimal Range
Set your personal optimal CFS window per river — custom ranges are a Pro feature.Upgrade to Pro →
Data Quality

River conditions are community-verified. CFS ranges, difficulty ratings, and trip sections may not reflect every flow level or seasonal change. Always check current conditions, scout unfamiliar rapids, and paddle within your skill level. If you spot an error, use the Improve This River button at the top of the page — your local knowledge is what makes this atlas accurate.