Post Office - Fergus Falls 118 S Mill St Ste 102 Fergus Falls, MN 56537 Phone : (218) 736-4714 Business Category Post Offices Toll-Free           (800) ASK-USPS Fax           (218) 739-0286 Passport Application Services - Fergus Falls 118 S Mill St Ste 102 Fergus Falls, MN 56537 Phone : (218) 736-4714 Business Category Passport Application Services Toll-Free           (800) ASK-USPS Fax           (218) 739-0286