MISSOURI RIVER: Latitude = 38.808424, Longitude = -90.116050, Zoom=13

River Mile Point(s)
Statute Miles Nautical Miles  Kilometers

Right Clicking anywhere on the map displays latitude, longitude, and address at that location:
The mouth of the Missouri River is just above St. Louis, MO, at Upper Mississippi River mile 195 on the right descending bank. This viewer covers most of the navigable portion, to just past Sioux City, Iowa.