Located in the eastern south-central US, the Commonwealth of Kentucky is the smallest of the eight south-central states and ranks 37th in size among the 50 states.
The total area of Kentucky is 40,409 sq mi (104,659 sq km), of which land makes up 39,669 sq mi (102,743 sq km) and inland water 740 sq mi (1,917 sq km). Kentucky extends about 350 mi (563 km) E-W; its maximum N-S extension is about 175 mi (282 km).
Kentucky is bordered on the N by Illinois, Indiana, and Ohio (with the line roughly following the north bank of the Ohio River); on the NE by West Virginia (with the line formed by the Big Sandy and Tug Fork rivers); on the SE by Virginia; on the S by Tennessee; and on the W by Missouri (separated by the Mississippi River). Because of a double bend in the Mississippi River, about 10 sq mi (26 sq km) of SW Kentucky is separated from the rest of the state by a narrow strip of Missouri.
After 15 years of litigation, Kentucky in 1981 accepted a US Supreme Court decision giving Ohio and Indiana control of at least 100 feet (30 meters) of the Ohio River from the northern shore. This in effect returned Kentucky's border to what it was in 1792, when Kentucky entered the Union.
The total boundary length of Kentucky is 1,290 mi (2,076 km). The state's geographic center is in Marion County, 3 mi (5 km) nw of Lebanon.