It travels 6.9 miles (11.1 km) in the shape of a capital J, starting northwest, veering northeast, and then turning north, serving the communities of Lutcher and Gramercy and providing a connection to Interstate 10 (I-10) for those towns.

With the exception of the area immediately north and south of its intersection with Airline Highway, LA-641 is an undivided two-lane route in its entirety.

The southern part of the highway remains in its same 1955-era routing, using Albert Street and Main Street; however, the route originally returned to LA-44 by crossing the Illinois Central Railroad just east of LA 20 (present day LA 3274).

With the completion of the Gramercy Bridge (or Veterans Memorial Bridge) across the Mississippi River between Gramercy and Wallace, the new state highway (LA 3213) intersected with LA 641 just south of the Kansas City Southern Railway.

The northern part of the road, albeit the most rural, serves as a connector route to industrial interests along Airline Highway and River Road in St. James and St. John parishes, the Gramercy Bridge, and plantation sightseeing on both sides of the Mississippi River.