33 C.F.R. § 3.40-40
Sector Upper Mississippi River's office is located in St. Louis, MO. Subject to the overriding provisions of § 3.40-5 , the boundaries of Sector Upper Mississippi River's Marine Inspection Zone and Captain of the Port Zone include all of Wyoming except for Sweetwater County; all of North Dakota, South Dakota, Nebraska, Colorado, Kansas, and Iowa; all of Missouri with the exception of Perry, Cape Girardeau, Scott, Mississippi, New Madrid, Dunklin, and Pemiscot Counties; that part of Minnesota south of latitude 46°20'00" N; that part of Wisconsin south of latitude 46°20'00" N, and west of longitude 90°00'00" W; that part of Illinois west of longitude 90°00'00" W and north of latitude 41°00'00" N; that part of Illinois south of latitude 41°00'00" N, except for Jackson, Williamson, Saline, Gellatin, Union, Johnson, Pope, Hardin, Alexander, Pulaski, and Massac Counties; that part of the Upper Mississippi River above mile 109.9, including both banks, and that part of the Illinois River below latitude 41°00'00" N.
33 C.F.R. §3.40-40