U.S. 51 travels 69 miles northward from Laplace to Hammond, Independence, Amite, Tangipahoa and Kentwood in southeastern Louisiana. The route shares an alignment with Interstate 55 north from outside Laplace to a bypass west of Ponchatoula. The remainder of U.S. 51 parallels the freeway to the east from Hammond to the Mississippi state line.
Bridges carrying I-55/U.S. 51 and Old U.S. 51 across Pass Manchac, a channel linking Lake Maurepas with Lake Pontchartrain. 05/09/15
Until 1951, U.S. 51 joined U.S. 61 and U.S. 65 from Laplace southeast to New Orleans. The overlaps of U.S. 51/65 along U.S. 61 were established to guide through travelers northward to Mississippi.
U.S. 51 Louisiana Guides
U.S. 51 Business
The 8.6 mile business route for U.S. 51 follows the pre-1965 alignment of the US highway through both Ponchatoula and Hammond. U.S. 51 Business separates from I-55/U.S. 51 at Exit 23 and runs northward along Railroad Avenue to Pine Street (LA 22) west in Downtown Ponchatoula. LA 22/U.S. 51 Business overlap west to Veterans Avenue, which extends the business route north from Ponchatoula to Hammond and Interstate 12 at Exit 40. Through Hammond, U.S. 51 Business follows SW Railroad Avenue to Downtown, where it joins U.S. 190 along a couplet on Thomas Street west / Morris Avenue. U.S. 51 Business and U.S. 190 overlap 1.25 miles west to the commercialized intersection with U.S. 51 (Morrison Boulevard).
| South |
 | U.S. 51 shield posted at the intersection of Oak Street and U.S. 190 (Morris Avenue) east in Downtown Hammond. U.S. 51 Business is routinely signed as the U.S. 51 mainline in Hammond. 11/20/08 |
 | U.S. 51 Business (Oak Street) south at Coleman Avenue and Zemurray Park. 11/20/08 |
 | U.S. 51 Business curves southeast from Oak Street to join Railroad Avenue ahead of 1st Avenue. 11/20/08 |
 | Following Railroad Avenue, a five lane arterial, U.S. 51 Business advances to a signalized intersection with Old Covington Highway. Old Covington Highway east from Hammond was once a part of LA 1067. 11/20/08 |
 | A myriad of traveler services line U.S. 51 Business (Railroad Avenue) ahead of a dumbbell interchange with Interstate 12. 11/20/08 |
 | The adjacent Hammond Square retail complex adds to the traffic congestion along U.S. 51 Business (Railroad Avenue) south at Interstate 12. 11/20/08 |
Photo Credits:
11/20/08 by AARoads
Connect with:
Interstate 10
Interstate 12
Interstate 55
U.S. 61
U.S. 190
Page Updated 10-04-2016.