Interstate 59 (United States)

Interstate 59 (United States)
State	AL
State2	MS
State3	LA
Route	59
Length mi	445.23
Established	1957
Direction a	South
Terminus a	near Slidell, Louisiana
Direction b	North
Terminus b	near Birmingham, Alabama
Counties	St. Tammany Parish, Pearl River County, Hancock County, Mississippi, Jackson County, Mobile County, Alabama, Jefferson County, Alabama
Previous route	58
Next route	60

Interstate 59 (United States) is an Interstate Highway in the United States that runs northeast–southwest through portions of Louisiana, Mississippi, and Alabama. The route connects the Gulf Coast region around New Orleans and Slidell with the industrial and population centers near Mobile, Alabama and the metropolitan area of Birmingham, Alabama. It functions as a regional arterial linking ports, military installations, university towns, and transportation corridors such as Interstate 10, Interstate 65, and Interstate 20.

Route description

Interstate 59 begins at a junction near Slidell where it interfaces with Interstate 10, providing connections to New Orleans, Metairie, Kenner, Louis Armstrong New Orleans International Airport and the Mississippi Gulf Coast including Biloxi and Gulfport. Entering Mississippi, the route passes near Hattiesburg, Laurel, and Pearl River County, intersecting with U.S. 11 and U.S. 49 which serve Southeastern Louisiana University, University of Southern Mississippi, and nearby defense facilities like Keesler Air Force Base. In Alabama the highway traverses Mobile County and Jefferson County, providing access to Mobile, Prichard, Tupelo (via connecting routes), and the Birmingham area where I-59 merges with Interstate 20 along the Red Mountain Expressway corridor to serve destinations including UAB, Vulcan Park and Museum, and the Birmingham–Shuttlesworth International Airport via auxiliary interchanges.

History

Planning for east–west and diagonal corridors in the post-Federal-Aid Highway Act of 1956 era identified the need for a route connecting the Gulf Coast to inland industrial centers. Early routing studies involved cooperation among the Louisiana Department of Transportation and Development, the Mississippi Department of Transportation, and the Alabama Department of Transportation (ALDOT) to address freight access to ports such as the Port of Mobile and military logistics for installations like Fort Rucker and NAS Meridian. Construction phases in the 1960s and 1970s followed segments of the historic U.S. Highway system corridors, with notable engineering projects including river crossings over the Pearl River and wetlands mitigation near the Bon Secour National Wildlife Refuge. Major urban completions in the 1980s and 1990s addressed bottlenecks near Hattiesburg and Birmingham, while storm resilience upgrades were prompted by damage from events such as Hurricane Katrina and Hurricane Camille.

Future and planned improvements

Planned improvements combine capacity projects, interchange reconstructions, and resilience measures coordinated among FHWA, ALDOT, MDOT, and LA DOTD. Projects slated include widening segments approaching Birmingham to relieve merging traffic with Interstate 20, interchange redesigns near Mobile to improve access to the Port of Mobile and Brookley Aeroplex, and bridge rehabilitations over the Tombigbee River and other waterways to meet updated load and seismic standards influenced by guidance from the American Association of State Highway and Transportation Officials (AASHTO). Freight-focused initiatives align with the U.S. DOT freight plans and regional metropolitan planning organizations such as the Northwest Alabama Metropolitan Planning Organization.

Exit list

The exit list for I-59 includes major interchanges with Interstate 10 at its southern terminus near Slidell; connections to U.S. 98 serving Gulfport and Biloxi; an interchange with U.S. 49 near Hattiesburg providing access to Gulf Coast Community College and Camp Shelby National Guard Site; and northern junctions where I-59 converges with Interstate 20 and Interstate 65 in the Birmingham metropolitan area. Additional exits serve municipalities such as Franklin County communities, Laurel, Tylertown, Meridian (via connectors), Mobile, Prichard, Gadsden (via connecting routes), and suburbs like Hoover.

Auxiliary routes

Auxiliary routes tied to the corridor and regional network include spur and loop designations and concurrent segments with other Interstates. Notable linked routes include Interstate 459 in the Birmingham area, which provides a southern bypass for traffic to Vestavia Hills and Hoover; connector segments with I-165 near Mobile that interface with the Bankhead Tunnel approach; and business routes that link to downtowns such as Hattiesburg and Laurel. These auxiliary corridors support access to institutions like University of Alabama at Birmingham, University of Southern Mississippi, and the United States Coast Guard facilities on the Gulf Coast.

Traffic volume and safety

Traffic volumes vary from rural two-lane-equivalent flows in portions of Pearl River County to high-density urban sections near Birmingham and Mobile, with peak average annual daily traffic increases influenced by freight moves to the Port of New Orleans and Port of Mobile. Safety interventions have included interchange lighting upgrades, installation of cable barriers recommended by the National Highway Traffic Safety Administration, resurfacing projects using AASHTO pavement design guidance, and enforcement partnerships with state police agencies such as the Alabama Law Enforcement Agency and the Mississippi Highway Patrol. Crash reduction strategies emphasize incident management coordinated with State Emergency Management Agency operations during hurricane evacuations and major events at venues like Legion Field.

Major junctions and communities served

I-59 serves a chain of communities and major junctions: at its southern end the Interstate 10 interchange near Slidell and access to New Orleans; through Harrison County corridors near Gulfport and Biloxi via connecting routes; the Hattiesburg interchange area serving University of Southern Mississippi and Forrest General Hospital; the Laurel and Lauderdale County sections providing freight links to timber and manufacturing centers; and northern termini in the Birmingham metropolitan area connecting with Interstate 20, Interstate 65, and Interstate 459 to serve Birmingham health, education, and industrial districts including Birmingham Southern College and Regions Field.

Category:Interstate Highways