The western section of the route connects the rural community of Evangeline with LA 91 at a point south of Iota.

East of Egan, LA 100 parallels the interstate to the northwest corner of Crowley, the parish seat.

Now known as Shelly Road, LA 100 continues east as the area transitions from pine forest to farmland.

[2][3][4] The highway then passes through a point known as Lawson, where it crosses the Acadiana Railway (AKDN) tracks and intersects LA 1121 (Oro Trail Road).

After crossing a bridge over Bayou Plaquemine Brule, the highway briefly skirts the northern city limit of Crowley, the parish seat.

[3][6] Like LA 100, Route 370 had a western section that ran east–west, but it was located 4.5 miles (7.2 km) to the north and passed through Iota rather than Evangeline.

[3][10] The eastern terminus at LA 13 was also slightly altered to accommodate the diamond interchange with I-10 constructed in 1963.

[3][10][11] La DOTD is currently engaged in a program that aims to transfer about 5,000 miles (8,000 km) of state-owned roadways to local governments over the next several years.

[12] Under this plan of "right-sizing" the state highway system, the western and eastern ends of LA 100 are proposed for deletion as they do not meet a significant interurban travel function.