In St. Landry Parish, US 167 and LA 10 intersect and briefly run concurrently with LA 103 south of Grand Prairie. After proceeding southeast through Plaisance, the route intersects LA 749, which heads south into Opelousas. Shortly afterward, at a point known as Nuba, the long concurrency of US 167 and LA 10 ends at an intersection with LA 182. US 167 continues east a short distance to I-49 and follows the interstate through Opelousas to Lafayette. Meanwhile, LA 10 turns north to follow LA 182 into the small town of Washington, situated on Bayou Courtableau. The route passes through the historic town center along Main Street and intersects LA 103, the town's connection to I-49, a second time. LA 10 and LA 182 proceed northeast across a bridge over Bayou Courtableau, exiting Washington. later, after curving due north, the route enters into an interchange with I-49 at Exit 27, connecting to Opelousas and Alexandria. After intersecting LA 745 (Thistlethwaite Boy Scout Camp Road) at Macland, LA 10 and LA 182 separate at a point known as Beggs.