A swamp the size of a small state
The U.S. Geological Survey calls the Atchafalaya Basin the largest contiguous river swamp in the country. It lies between Baton Rouge and Lafayette and covers more than 1.4 million acres, 885,000 of them forested wetland inside the floodway. The USGS counts over 100 kinds of finfish and shellfish here, and some lower basin waters hold more than 1,000 pounds of finfish per acre.
Henderson is the levee town, and parish tourism calls it the way into the basin. After the Great Flood of 1927 and the levees of the 1930s, families from the old Village of Atchafalaya moved to higher ground. The settlement appeared on 1940s maps as New Henderson Landing and was incorporated in 1971. Its longtime mayor, a fisherman himself, told parish tourism that other St. Martin Parish towns farmed while Henderson always fished.
Butte La Rose, just east off Interstate 10, is the only community in the parish still between the basin levees. It is mostly a weekend place, with three free parish boat ramps open around the clock and the Atchafalaya Welcome Center at the exit. The small community of Catahoula keeps a public launch at Clayton Boudreaux Memorial Park, and its lake and bayous draw fishermen all year.
The food follows the fishing. Henderson levee restaurants serve catfish, gumbo, étouffée, alligator bites and crawfish every way, and the Atchafalaya Club at Pat's Fisherman's Wharf has held weekend zydeco and swamp pop dances since 1948.
The wild catch runs on river water
LSU researchers report that roughly nine in ten of the state's wild caught crawfish have historically come out of this basin. Pond crawfish follow the farmer; wild ones follow the river. Louisiana Sea Grant explains that trappers need spring floods high enough to reach the back waterways but not so high the swamp is unworkable, and that landings climb around Easter and fade by July. A 2015 legislative resolution noted that the state sets no specific wild crawfish season and asked LDWF to study one.
Water is managed here too. In 2026 LDWF and St. Martin Parish Government lowered Henderson Lake three feet between August 24 and November 2 to fight invasive plants and improve spawning habitat. Record rain upstream pushed the start back, and the state closed the Butte La Rose boat landing on September 7 because the water was too low.
