Interstate 12 (I-12) is an intrastate Interstate Highway located entirely within the US state of Louisiana. It spans a total of 85.59 miles (137.74 km) in an east–west direction from I-10 in Baton Rouge to an interchange with both I-10 and I-59 in Slidell. Along the way, it passes through the city of Hammond, where it intersects I-55 and US Route 51 (US 51). It also serves the cities of Ponchatoula and Denham Springs, as well as the St. Tammany Parish cities of Covington and Mandeville.
U.S. Highway 171 (US 171) is a part of the United States Numbered Highway System and the only route within that system currently located entirely within the state of Louisiana. It spans 177.44 miles (285.56 km) in a north–south direction from the junction of US 90 and Louisiana Highway 14 (LA 14) in Lake Charles to the junction of US 79/US 80 and LA 3094 in Shreveport.
U.S. Route 190 (US 190) is an east–west United States Highway in Louisiana and Texas. Segments of US 190 will be upgraded to Interstate 14 (I-14); the first 24.8-mile (39.9 km) segment was opened on January 26, 2017.
Airline Highway is a divided highway in the U.S. state of Louisiana, built in stages between 1925 and 1953 to bypass the older Jefferson Highway. It runs 115.6 miles (186.0 km), carrying U.S. Highway 61 from New Orleans northwest to Baton Rouge and U.S. Highway 190 from Baton Rouge west over the Mississippi River on the Huey P. Long Bridge. US 190 continues west towards Opelousas on an extension built at roughly the same time.
Louisiana Highway 10 (LA 10) is a state highway located in southern Louisiana. It runs 255.51 miles (411.20 km) in an east–west direction from U.S. Highway 171 (US 171) south of Leesville to the Mississippi state line east of Bogalusa.
Louisiana Highway 29 (LA 29) is a state highway located in southern Louisiana. It runs 54.09 miles (87.05 km) in a north–south direction from LA 13 north of Eunice to LA 114 west of Moreauville.
Interstate 55 (I-55) is a part of the Interstate Highway System that spans 964.25 miles (1,551.81 km) from LaPlace, Louisiana, to Chicago, Illinois. Within the state of Louisiana, the highway travels 66 miles (106 km) from the national southern terminus at I-10 in LaPlace to the Mississippi state line north of Kentwood.
Louisiana Highway 81 (LA 81) is a state highway located in Pointe Coupee Parish, Louisiana. It runs 8.82 miles (14.19 km) in a generally north–south direction from LA 77 in Livonia to a second junction with LA 77 in Fordoche.
U.S. Highway 51 (US 51) is a part of the United States Numbered Highway System that spans 1,277 miles (2,055 km) from LaPlace, Louisiana to a point north of Hurley, Wisconsin. Within the state of Louisiana, the highway travels 69.12 miles (111.24 km) from the national southern terminus at US 61 in LaPlace to the Mississippi state line north of Kentwood.
U.S. Highway 65 (US 65) is a part of the United States Numbered Highway System that spans 966 miles (1,555 km) from Clayton, Louisiana to Albert Lea, Minnesota. Within the state of Louisiana, the highway travels 100.77 miles (162.17 km) from the national southern terminus at US 425/LA 15 in Clayton to the Arkansas state line north of Lake Providence.
Louisiana Highway 64 (LA 64) is a state highway located in southeastern Louisiana. It runs 20.45 miles (32.91 km) in a general east–west direction from LA 964 in Zachary to the junction of LA 16 and LA 1026 north of Denham Springs.
U.S. Highway 61/190 Business is a business route of both U.S. Route 61 and U.S. Route 190 in Louisiana that serves as a boulevard into downtown Baton Rouge. It spans 10.89 miles (17.53 km) in a southeast to northwest direction and it is signposted as Business 61/190, generally without directional shields. It follows parts of the former alignment of US 61/190 through Baton Rouge, which existed in downtown Baton Rouge from 1935 until 1960.
Louisiana Highway 103 is a state highway in St. Landry Parish, Louisiana, United States, that spans 39.5 miles (63.6 km) in a wide semi-circle around the north side of Opelousas. The route is not bannered but runs in an overall west–east direction from U.S. Highway 190 near Lawtell to LA 31 in Leonville. Along the way, it passes through the towns of Washington and Port Barre.
Louisiana State Route 7 was one of the 98 original state highways that were established in 1924. It was split into two separate segments, with the western section running in a west to east direction for 110.80 miles (178.32 km), spanning from Deweyville to the Atchafalaya River. The eastern section ran for 144.50 miles (232.55 km) from Lottie to the Mississippi state line, in a west to east direction.
