It runs in a west to east direction for a total length of 29.5 miles (47.5 km).

The highway is recognized by the United States Department of Transportation as San Bernardo Scenic Byway.

It crosses the Industrial Canal via the St. Claude Avenue Bridge and runs through the city's Lower 9th Ward, continuing to parallel to the Mississippi River.

The two highways run concurrently for two miles (3 km) near the end of East Judge Perez Drive, at which point LA 46 turns east through the community of Reggio and LA 300.

The route again widens to four lanes and becomes a divided highway from the westernmost intersection with the LA 300/Bayou Road to the easternmost intersection with LA 300/Bayou Road before narrowing again to an undivided, two-lane roadway from the easternmost intersection with LA 300/Bayou Road to the eastern terminus at Shell Beach.