Atchafalaya Basin
St. Martin / Iberia Co. · 140 mi · Class I
165,000CFS/ 12.92 ft
Optimal→Stable
Optimal: 50000–200000 CFS · USGS #07381490
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Difficulty
Optimal
Avg Flow
Hist. Median
USGS Gauge
Atchafalaya National Heritage Area · National Wildlife Refuge
The largest river swamp in North America — 140 miles of labyrinthine bayous, cypress-tupelo forests, and vast floodplain stretching across south-central Louisiana. The Atchafalaya carries roughly 30% of the Mississippi River's flow through a primordial landscape that feels unchanged since the Pleistocene.
Trip sections
Upper Basin — Simmesport to Henderson, open swamp channels
Henderson Swamp — lake-like expanse, iconic cypress groves
Lower Basin — Morgan City to Atchafalaya Bay, tidal marshes
Outfitters
Atchafalaya Basin Landing
Guided swamp tours and kayak rentals, Henderson
Pack & Paddle
Lafayette-based outfitter, basin trips
72-Hour Flow Forecast
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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.