Louisiana Highway 18

Louisiana Highway 18
Route information
Maintained by Louisiana DOTD
Length	79.7 mi[1] (128.3 km)
Existed	1955 renumbering–present
Major junctions
West end	LA 1 / LA 3089 in Donaldsonville
Major intersections	LA 20 in North Vacherie LA 3213 in Wallace LA 640 in Edgard I-310 in Luling US 90 in Bridge City LA 45 in Marrero LA 3017 in Harvey
East end	US 90 Bus. / Future I-49 / LA 23 in Gretna
Location
Country	United States
State	Louisiana
Parishes	Ascension, St. James, St. John the Baptist, St. Charles, Jefferson
Highway system
Louisiana State Highway System Interstate US State Scenic
← LA 17 → LA 19

Louisiana Highway 18 (LA 18) is a state highway that serves Ascension, St. James, St. John the Baptist, St. Charles, and Jefferson Parishes. Called the Great River Road, it runs from west to east, parallel to the west bank of the Mississippi River, running from Donaldsonville to Gretna. It spans a total of 79.7 miles (128.3 km).^[1] In the more rural parts of LA 18's span, it is commonly referred to as River Road, but it becomes 4th Street once it enters Westwego.

LA 18 begins as an undivided, two lane road in downtown Donaldsonville as Bayou Road, which runs parallel to the Mississippi River. It intersects with the Sunshine Bridge (LA 70) east of Donaldsonville, the Veterans Memorial Bridge (LA 3213) in Wallace, and Interstate 310 near Luling as it continues downriver. At Bridge City, LA 18 leaves the river and briefly merges with U.S. Highway 90 northbound, then turns east along Seven Oaks Blvd. while U.S. 90 crosses the Mississippi River via the Huey P. Long Bridge. LA 18 meets and briefly cojoins the alternate river road, LA 541. When LA 18 enters Westwego, LA 18 becomes 4th Street but still continues parallel to the river. In Gretna, LA 18 turns south, away from the river: first onto Huey P. Long Avenue for one block, then east along 5th Street to Lafayette Street. LA 18 then goes south and ends at the intersection of Lafayette St. and the Westbank Expressway.

Between the junction with LA 52 in Luling and Huey P. Long Avenue in downtown Gretna, LA 18 is largely the original routing of U.S. Highway 90 (also LA 2 before the 1955 renumbering) and before that, the Old Spanish Trail highway. (One notable exception is that LA 18 is routed along Louisiana Street rather than the parallel Sala Avenue through Westwego's historic district.)

Parish	Location	mi[1]	km	Destinations	Notes
Ascension	Donaldsonville	0.0	0.0	LA 1 (West 10th Street) – Thibodaux, Plaquemine LA 3089 east (Marchand Drive)	Western terminus; Western terminus of LA 3089
	​	3.1	5.0	LA 3120	Northwestern terminus of LA 3120
St. James	​	8.3	13.4	LA 70 – Donaldsonville, Sorrento	LA 70 passes overhead via Sunshine Bridge across Mississippi River; indirect access via frontage road
	Lagan	20.4	32.8	LA 3219	Northern terminus of LA 3219
	North Vacherie	26.5	42.6	LA 20 west – Thibodaux	Eastern terminus of LA 20
St. John the Baptist	Wallace	30.9	49.7	LA 3213 north to I-10 – Gramercy LA 3213 south – Donaldsonville	Interchange; LA 3213 passes overhead via Gramercy Bridge over Mississippi River
	​	33.9	54.6	LA 639	Northern terminus of LA 639; Unsigned junction
	Edgard	38.9	62.6	LA 640 north	West end of LA 640 concurrency; Until 2013, LA 640 crossed Mississippi River via Reserve-Edgard Ferry to LA 44 and LA 53
		39.1	62.9	LA 640 south	East end of LA 640 concurrency
St. Charles	Killona	46.1	74.2	LA 3141 (Mary Plantation Road)	Northern terminus of LA 3141
	Taft	48.2	77.6	LA 3142	Northern terminus of LA 3142; Unsigned junction
	Hahnville	51.8	83.4	LA 3160 (Home Place)	Northeastern terminus of LA 3160
	Luling	55.1	88.7	I-310 north – New Orleans I-310 south to US 90 – Boutte	Interchange; I-310 passes overhead via Luling Bridge across Mississippi River
		55.8	89.8	LA 52 (Paul Maillard Road) – Boutte	Northern terminus of LA 52
		57.3	92.2	LA 3060 (Barton Avenue)	Northern terminus of LA 3060
Jefferson	​	69.7	112.2	LA 541 (River Road) – Bridge City	Western terminus of LA 541
	​	70.1	112.8	US 90 west – Boutte	West end of U.S. 90 concurrency
	Bridge City	71.0	114.3	US 90 east – New Orleans	East end of U.S. 90 concurrency; At Huey P. Long Bridge across Mississippi River
	Westwego	72.3	116.4	LA 541 (River Road)	West end of LA 541 concurrency
		72.8	117.2	LA 541 (River Road)	East end of LA 541 concurrency
		73.3	118.0	LA 18 Spur (Louisiana Street)	Northern terminus of LA 18 Spur
	Marrero	76.3	122.8	LA 45 south (Barataria Boulevard) to US 90 Bus. (West Bank Expressway)	Northern terminus of LA 45; Junction includes incorrect signage
		76.6	123.3	LA 560-2 (Barataria Boulevard)	Southern terminus of LA 560-2
	Harvey	77.6	124.9	LA 3018 (Destrehan Avenue)	Northern terminus of LA 3018; Unsigned junction
		77.6	124.9	LA 541 (Destrehan Avenue)	Eastern terminus of LA 541
		77.7	125.0	Bridge over Harvey Canal
		77.8	125.2	LA 3017 (Peters Road, Bark Street)	Northern terminus of LA 3017
	Gretna	79.2	127.5	LA 466 (5th Street)	Western terminus of LA 466; Unsigned junction
		79.7	128.3	US 90 Bus. (West Bank Expressway) – New Orleans LA 23 (Lafayette Street, West Bank Expressway) – Belle Chasse	Southern terminus; Partially unsigned junction
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus       Incomplete access

Louisiana Highway 18 Spur
Location	Westwego
Length	0.62 mi[1] (1,000 m)
Existed	1960s–present

In Westwego, LA 18 turns from Louisiana Street onto 4th Street. LA 18 Spur continues southward for 0.6 miles (0.97 km)^[1] on Louisiana Street until it meets the Westbank Expressway (U.S. 90 Business).

The entire highway is in Westwego, Jefferson Parish.

mi[1]	km	Destinations	Notes
0.00	0.00	LA 18 (Louisiana Street, 4th Street)	Northern terminus
0.62	1.00	US 90 Bus. (West Bank Expressway) – New Orleans	Southern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

• La DOTD State, District, and Parish Maps
  • District 02
  • District 61
  • District 62
  • Ascension Parish
  • St. James Parish
  • St. John the Baptist Parish
  • St. Charles Parish
  • Jefferson Parish (North Section)