It runs 8.75 miles (14.08 km) in a north–south direction from U.S. Highway 425 (US 425) north of Bastrop through Beekman to the Arkansas state line.

While LA 142 heads northwest toward Crossett, US 425 travels in a slightly northeastern trajectory to the smaller city of Hamburg.

It proceeds northwest for just under 2.0 miles (3.2 km) before curving slightly to the west and passing through a sparsely populated area along the Arkansas, Louisiana and Mississippi Railroad known as Beekman.

Shortly afterward, the highway curves more to the north and continues for 2.4 miles (3.9 km) before reaching the Arkansas state line.

[2][3][4] The route is classified as a rural minor arterial by the Louisiana Department of Transportation and Development (La DOTD) with an average daily traffic volume in 2013 of 3,400 vehicles.