Background

The U.S. Postal Service’s mission is to provide timely, reliable, secure, and affordable mail and package delivery to more than 160 million residential and business addresses across the country. The U.S. Postal Service Office of Inspector General (OIG) reviews delivery operations at facilities across the country and provides management with timely feedback in furtherance of this mission. 

This interim report presents the results of our audit of delivery operations and property conditions at the O’Fallon Main Post Office (MPO) in O’Fallon, MO. We selected the St. Louis area based on a congressional inquiry issued April 1, 2025, from U.S. senators and representatives from Missouri to conduct an audit of post offices and distribution centers in the St. Louis metro area. The O’Fallon MPO is in the Kansas-Missouri (KS-MO) District of the Central Area and serves about 122,121 people in ZIP Codes 63366, 63367, and 63368 which are considered predominantly urban areas (see Figure 1). Specifically, 117,632 (96 percent) live in urban communities and 4,529 (four percent) live in rural communities.