Green River
🏞 National Park
Hart / Edmonson / Butler Co. · 384 mi · Class I–II
510CFS/ 3.17 ft
Optimal
→Stable
Optimal: 300–1200 CFS · USGS #03308500
⚡Flow data is live from USGS·Rapid classifications and CFS ranges need community verification·Know this river?
384 mi
Length
Class I–II
Difficulty
300–1200 cfs
Optimal
1,850 cfs
Avg Flow
1,700 cfs
Hist. Median
#03308500
USGS Gauge
Mammoth Cave National Park · UNESCO World Heritage Site · International Biosphere Reserve

Kentucky's longest river at 384 miles — flows through the heart of Mammoth Cave National Park in one of the most geologically extraordinary landscapes on earth. A 25-mile wilderness canoe route through Mammoth Cave NP is one of the most unique paddling experiences in America — floating above the world's longest known cave system.

Trip sections
Munfordville to Mammoth Cave NP — Class I–II, approach
Inside Mammoth Cave NP — 25 mi, spring-fed, crystal clear
Below Brownsville — Class I, widening valley
Outfitters
Green River Canoe Rental
Mammoth Cave area canoe trips
Mammoth Cave Adventures
Park canoe concession
72-Hour Flow Forecast
NOAA NWPS
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10-Year Flow Patterns
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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.