It runs 44.03 miles (70.86 km) in a southwest to northeast direction from U.S. Highway 80 (US 80) in Ruston to the Arkansas state line north of Marion.

This created a single highway designation connecting the seats of Lincoln and Union parishes to each other and with the Arkansas state line.

It heads northeast on Farmerville Highway, an undivided four-lane thoroughfare, and passes through a diamond interchange with I-20 at exit 86.

Gaining a center turning lane, LA 33 proceeds through a growing commercial corridor that extends out of the Ruston city limits.

[2][4][5] LA 33 continues northeast for about 11 miles (18 km) through sparsely populated pine forests before reaching the town of Marion.

[7] Daily traffic volume in 2013 peaked at 18,600 vehicles in Ruston and 11,600 in Farmerville, tapering down to 1,010 near the Arkansas state line.

[12] In May 2013, Louisiana Governor Bobby Jindal signed a bill into law renaming the bridge in honor of James Peyton Smith, the state representative from Union and Morehouse parishes from 1964 to 1972.

This portion of I-20, extending 7.8 miles (12.6 km) from Ruston to Choudrant, was the first rural segment of interstate highway to be completed in Louisiana.

[16][17] LA 33 was subsequently widened southward from the interchange to handle the increased traffic, which included the replacement of the original two-lane overpass across I-20 with the current five-lane span in 1991.