Passport Application Services - Custer 413 2nd Ave Custer, MT 59024 Phone : (406) 856-4151 Business Category Passport Application Services Toll-Free           (800) ASK-USPS Post Office - Custer 413 2nd Ave Custer, MT 59024 Phone : (406) 856-4151 Business Category Post Offices Toll-Free           (800) ASK-USPS