Located in the western north-central US, Iowa is the smallest of the midwestern states situated W of the Mississippi River, and ranks 25th in size among the 50 states.
The total area of Iowa is 56,275 sq mi (145,752 sq km), of which land takes up 55,965 sq mi (144,949 sq km) and inland water 310 sq mi (803 sq km). The state extends 324 mi (521 km) E-W; its maximum extension N-S is 210 mi (338 km).
Iowa is bordered on the N by Minnesota; on the E by Wisconsin and Illinois (with the line formed by the Mississippi River); on the S by Missouri (with the extreme southeastern line defined by the Des Moines River); and on the W by Nebraska and South Dakota (with the line demarcated by the Missouri River and a tributary, the Big Sioux).
The total boundary length of Iowa is 1,151 mi (1,853 km). The state's geographic center is in Story County near Ames.