It proceeds north along the two-lane, undivided Prairie Ronde Highway and immediately crosses the Union Pacific Railroad (UPRR) tracks.

LA 103 turns northwest to follow US 167/LA 10 briefly before resuming its northeastern course, now known as Grand Prairie Highway.

After three blocks, LA 103 narrows to a four-lane, undivided highway for a short distance before dividing again through an interchange with Interstate 49 (I-49) at Exit 25.

LA 103 enters Port Barre on Saizan Avenue, the town's main thoroughfare, and follows it as it turns southwest and crosses a bridge over Bayou Courtableau.

[5][6][7][8][9] LA 103 was created with the 1955 Louisiana Highway renumbering,[10] and its route has remained unchanged except for the portion running through Washington.

[11][12][13] Before the construction of I-49 north of Opelousas in the late 1980s, LA 103 followed a slightly different two-lane alignment on the east side of Washington.

After crossing a now-abandoned rail line, it followed the path of the current alignment briefly before turning northeast onto Elizabeth Street.

[14][15] Later, the St. Landry Veterans Memorial Highway was constructed to create a complete four-lane alignment between I-49 and LA 10/LA 182 (North Main Street).