The Platte River is located in southwest Iowa and northwest Missouri. It originates in Union County, Iowa and flows southward for about 200 miles where it meets with the Missouri River near the town of Farley, Missouri. The watershed contains 2,419 square miles with 786 square miles (32.5%) in Iowa and 1,633 square miles (67.5%) in Missouri. Major tributaries include the 102 River, Third Fork, Honey Creek, Castile Creek, and the Little Platte River. Streams within the basin are typical prairie type streams in that they are turbid and generally have homogeneous substrate consisting of silt and sand.
The basin is best characterized as rural with parts of the watershed lying within the cities of St. Joseph and Kansas City. Maryville is the largest urban area totally within the watershed, and it has a population of just over 10,000. Land use within the basin is dominated by agricultural practices and is comprised of about 60% row crop production, 17% pasture, and 11% forest.