United States Postal Service in Santee operates the city's primary post office at 9518 Mission Gorge Road, the sole full-service USPS retail location within the 92071 ZIP code. The facility processes domestic and international mail alongside specialized services used by area businesses, including certified mailings coordinated by accounting firms such as Uhart Tax & Financial on Prospect Avenue during peak tax-filing season. Passport acceptance services make the Santee branch a destination for new-passport and renewal applications, requiring two forms of identification and a passport-quality photograph. The 24-hour lobby provides continuous PO Box access for business and residential customers beyond retail counter hours, serving the Mission Gorge Road commercial corridor between Santee Trolley Square and the neighborhoods approaching Mission Trails Regional Park. Real estate transaction document routing connects the branch to the closing processes managed by firms such as Brenda Childress, Realtor at Town Center Parkway, where deed recordings and title transfers require certified or registered mail. Additional retail services include money orders, burial flag distribution for veterans' families, migratory bird Duck Stamps, and a self-service kiosk for postage and package processing.