Louisiana Highway 650 (LA 650) ran 3.5 miles (5.6 km) in a southeast to northwest direction between Gray and Schriever, Terrebonne Parish.

LA 650 briefly jogged to the east then back to the north, separating from Bayou Blue Bypass Road.

Louisiana Highway 651 (LA 651) ran 1.3 miles (2.1 km) in a north–south direction along Bowie Road in Raceland, Lafourche Parish.

Now a ghost town, Bowie once thrived around a lumber mill served by the rail line north of Raceland in the early 20th century.

[6] The route initially heads west from a boat launch on Bayou Cut Off then turns north and crosses US 90 via an overpass.

[10] The route heads northeast from LA 1 and immediately crosses a vertical lift bridge over Bayou Lafourche.

4.4 miles (7.1 km) later, LA 654 curves to the south and proceeds a short distance to a bridge at the Company Canal.

A private road crosses the canal and proceeds toward the Golden Ranch Plantation in Gheens.

It immediately crosses a swing bridge across Bayou Lafourche into the unincorporated community of Rita.

A spur, 0.44 miles (0.71 km) in length and signed as the mainline route, follows Vacherie Street in Lockport from the bridge to LA 1 (Crescent Avenue).

Louisiana Highway 656 (LA 656) ran 1.5 miles (2.4 km) in a west–east direction along Lake Long Drive near the Lafourche–Terrebonne Parish line northeast of Houma.

LA 20 had been realigned onto a new railroad overpass about five years earlier, eliminating the at-grade crossing with the rail line and the direct connection between the two highways.

The highway continues southeast to Presquille and a second intersection with LA 24, which crosses to the east bank of the bayou.

[23] The route heads northeast from an interchange with LA 315 (Bayou Dularge Road) and immediately crosses a swing bridge over the Houma Navigation Canal.

It then crosses a vertical lift bridge over Bayou La Carpe and enters the city of Houma where it travels along South Van Avenue.

A locally maintained vertical lift bridge crosses the bayou and connects to LA 659 (Park Avenue), which follows the opposite bank.

It immediately turns east, briefly running alongside US 90 Bus./LA 182 before resuming its northern course, now in a concurrency with US 90 Bus.

Louisiana Highway 664 (LA 664) runs 0.82 miles (1.32 km) in a north–south direction along St. Charles Street in Houma, Terrebonne Parish.

[26] The route begins at LA 311 (Little Bayou Black Drive) and proceeds north along the Houma–Bayou Cane line.

[17] LA 664 was created with the 1955 Louisiana Highway renumbering,[4] and its route has remained the same to the present day.

[27] The route initially heads northeast from LA 57 in an area known as Pointe Aux Chenes at the northern limit of Montegut.

After 1.1 miles (1.8 km), LA 665 turns to the southeast to run alongside Bayou Pointe Au Chien.

The highway continues for another 8.8 miles (14.2 km) to the Pointe Au Chien Landing at the Cutoff Canal.

After about three-quarters mile (1.2 km), the highway enters a residential neighborhood also passing by some city offices.

It crosses a railroad at-grade and passes a manufacturing plant before reaching an intersection with Main Street, LA 182.

The two highways head northwest along Main Street for about one-tenth mile (0.16 km) passing some businesses.

It crosses Bayou Teche on a small swing bridge, passes a few more houses and a church, and ends at LA 87.

The highway heads north passing a church and the small residential neighborhood comprising Patoutville.

Louisiana Highway 685 (LA 685) runs 7.70 miles (12.39 km) from Tigre Lagoon to Erath.

Near the midpoint of the highway, LA 688 crosses a small waterway and provides access to a boat launch.