LA 77 begins at LA 1 near The Island Country Club in Plaquemine and runs parallel with Bayou Jacob as it heads west.

Meeting Port Allen Lock, it crosses over the Bayou Grosse Tête Draw Bridge before heading north.

The highway then interchanges with I-10 at exit 139 before entering Rosedale and intersecting LA 76.

However, this shortcut is used to reach Morganza, to the northeast of Livonia.

[2] The entire highway is in Pointe Coupee Parish.