From the south, LA 3257 begins at the north bank of Bayou Rigolets and heads north along the west bank of Bayou Barataria. Towards the northern terminus, it meets LA 302. LA 302 provides its only links to any other state highway and the mainland via a swinging bridge over Bayou Barataria. Its northern end is at the south bank of Bayou Villars. LA 3257 was formerly the southerly portion of LA 301, although it is unclear whether both sections were ever connected.
LA 3257 is an undivided, two-lane road for its entire length.