# List of Interstate Highways in Louisiana

The Interstate Highway System in Louisiana consists of 933.84 miles (1,502.87 km) of freeways constructed and maintained by the Louisiana Department of Transportation and Development (La DOTD).
The system was authorized on June 29, 1956 when President Dwight D. Eisenhower signed into law the Federal Aid Highway Act of 1956. The Louisiana Department of Highways, predecessor of the DOTD, began construction shortly afterward on its portion of the system, to which approximately 686 miles (1,104 km) was initially allotted. The first road segment in the new system was officially opened and dedicated on February 24, 1960 and consisted of a portion of the Pontchartrain Expressway (I-10) in New Orleans. Two months later, the first Interstate Highway shields installed in Louisiana accompanied the opening of a portion of I-20 near Ruston on April 23.

## Primary interstates

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| I-10 | 274.42 | 441.64 | Texas state line at Orange, TX | Mississippi state line east of Slidell | 01960-01-011960 | current | Southern Louisiana's primary east–west route serving Lake Charles, Lafayette, Baton Rouge, New Orleans, and Slidell |
| I-12 | 85.59 | 137.74 | I-10 in Baton Rouge | I-10/I-59 in Slidell | 01967-01-011967 | current | Northern bypass of New Orleans metropolitan area via Hammond |
| I-14 | — | — | Texas state line near Leesville, LA (undecided) | Mississippi state line near Natchez, MS (undecided) | proposed | — | Proposed extension roughly paralleling the LA 28 corridor |
| I-20 | 189.87 | 305.57 | Texas state line west of Greenwood | Mississippi state line at Vicksburg, MS | 01960-01-011960 | current | Northern Louisiana's primary east–west route serving Shreveport and Monroe |
| I-49 | 239.25 | 385.04 | I-10/US 167 in Lafayette | Arkansas state line north of Ida | 01983-01-011983 | current | Louisiana's primary north–south route, connecting I-10 and I-20 via Alexandria; final gap in Shreveport is under construction and southern extension from Lafayette to New Orleans is planned |
| I-55 | 65.81 | 105.91 | I-10/US 51 in LaPlace | Mississippi state line north of Kentwood | 01960-01-011960 | current | North–south route in southeastern Louisiana via Hammond |
| I-59 | 11.48 | 18.48 | I-10/I-12 in Slidell | Mississippi state line north of Pearl River | 01962-01-011962 | current | North–south route in southeastern Louisiana via Slidell |
| I-69 | — | — | Texas state line southwest of Shreveport (undecided) | Arkansas state line northeast of Haynesville (undecided) | proposed | — | Proposed extension roughly paralleling the US 79 corridor |
| Former Proposed and unbuilt ||||||||

## Auxiliary interstates

| Number | Length (mi) | Length (km) | Southern or western terminus | Northern or eastern terminus | Formed | Removed | Notes |
| I-110 | 8.89 | 14.31 | I-10 in Baton Rouge | US 61 in Baton Rouge | 01964-01-011964 | current | Baton Rouge spur; formerly designated as I-410 |
| I-210 | 12.40 | 19.96 | I-10 west of Lake Charles | I-10 east of Lake Charles | 01964-01-011964 | current | Lake Charles downtown bypass |
| I-220 | 17.62 | 28.36 | I-20/LA 3132 in Shreveport | I-20 in Bossier City | 01977-01-011977 | current | Shreveport–Bossier City downtown bypass |
| I-310 | 11.25 | 18.11 | US 90/LA 3127 in Boutte | I-10 west of Kenner | 01983-01-011983 | current | Spur west of New Orleans |
| I-310 | 2.70 | 4.35 | US 90 Bus. in New Orleans | I-10 in New Orleans | 01964-01-011964 | 01969-01-011969 | Cancelled Vieux Carré Riverfront Expressway |
| I-410 | 1.90 | 3.06 | LA 67 in Baton Rouge | I-10 in Baton Rouge | 01961-01-011961 | 01964-01-011964 | Unfinished Baton Rouge loop partially retained as I-110; planned as 13.60-mile (21.89 km) route with western terminus at I-10 near Port Allen |
| I-410 | 48.5 | 78.1 | I-10 west of New Orleans | I-10 in Eastern New Orleans | 01969-01-011969 | 01977-01-011977 | Cancelled southern bypass of New Orleans known as the Dixie Freeway; partially built as current I-310 and I-510 |
| I-420 | 10.20 | 16.42 | I-20 in West Monroe | I-20 in Monroe | 01957-01-011957 | 01964-01-011964 | Cancelled two-lane bypass of Monroe |
| I-510 | 3.04 | 4.89 | LA 47 in New Orleans | I-10/LA 47 in New Orleans | 01992-01-011992 | current | Spur in Eastern New Orleans |
| I-610 | 4.52 | 7.27 | I-10 in New Orleans | I-10 in New Orleans | 01965-01-011965 | current | New Orleans downtown bypass |
| I-910 | 9.70 | 15.61 | US 90 Bus. in Marrero | I-10/US 90 Bus. in New Orleans | 01999-01-011999 | current | FHWA designation (not used by La DOTD) for freeway portion of US 90 Bus. and placeholder for future I-49 corridor |
| Former ||||||||