Fort Henry, Confederate fort built early in the American Civil War on the right bank of the Tennessee River, just south of the Kentucky-Tennessee boundary. Together with Fort Donelson it constituted the most important link in the first line of Confederate defense in the Mississippi Valley. Early in 1862, to gain control of the Mississippi Valley and split the Confederate states in two, the North planned the capture of the forts. General Ulysses S. Grant, in command of about 17,000 men on transports, and Commodore Andrew Foote, commanding a flotilla of gunboats, moved up the river to Fort Henry, which was defended by about 3000 men under General Lloyd Tilghman. On the morning of February 6, Foote attacked the fort alone, because the transports bearing Grant and his men were delayed. The garrison of the fort was enabled by the delay to withdraw by land to Fort Donelson, 19 km (12 mi) distant on the Cumberland River, leaving a small artillery detachment that returned the fire of the Union gunboats for more than an hour, until forced to surrender.