US Posts Offices no longer stay open late on Tax Day (thanks internet!), but there is one local office that will be open after 5p. You'll have to go the location in Lafayette for service until 5:30 PM.

USPS, 1105 Moss Street, Lafayette, LA 70501 -- 8:00a - 5:30p

There are two self-service kiosks in Acadiana, which can be used for the majority of mail transactions. One is in Lafayette and the other is in New Iberia.

817 E Dale Street, New Iberia, LA 70560 -- 24-Hour Service

455 Feu Follet Road, Lafayette, LA 70508 -- 5:00am - 9:00pm

Tax Day is two days later than normal. The 15th fell on Sunday and it was a holiday yesterday in Washington, DC. Happy filing!