During the Civil War, Patterson, Missouri, south of the Union encampment at Pilot Knob, became a regular Union post as part of the effort to maintain federal control of the area. In late 1862, Union Gen. John Davidson ordered Gen. William Plummer Benton and the 25th Missouri Infantry to fortify Patterson. The regiment turned a church into a storehouse enclosed by a palisade and built Fort Benton on a hill above it, a 100-foot-square earthen fort with trenches, timber-supported interior walls, a buried magazine, and light cannons. The 25th Missouri also improved roads, built bridges, and established a telegraph line. More than 7,000 Union troops camped north of Patterson along Camp Creek before the army moved south to Van Buren, leaving men behind to guard the post. In March 1863, the 3rd Missouri State Militia under Col. Edwin Smart replaced the Federal garrison. Confederate generals John Sappington Marmaduke and Sterling Price each attacked the fort during raids. In Marmaduke's raid, Col. George W. Carter's cavalry attacked Fort Benton at dawn on April 20, 1863, after surprising Union pickets south of the fort. Warned by cannon fire, Smart reinforced the pickets and temporarily checked the attackers while the rest of the encampment burned supplies and buildings before withdrawing north toward Pilot Knob. The Confederates pursued, and a running battle stretched seven miles to Stoney Battery, where Smart formed a line, sent troops to secure the bridge over Big Creek, and enabled his men to reform and disperse partisan forces. Confederate losses were about 25 and Smart reported about 50 losses, including missing and captured men; Fort Benton was soon reoccupied by Union troops after Marmaduke's defeat at Cape Girardeau and retreat to Arkansas. In late summer 1864, during Sterling Price's final raid into Missouri, Col. Joseph O. Shelby approached Fort Benton on September 22 while it was held by companies of the 47th Missouri Infantry and 3rd Missouri State Militia Cavalry. As the cavalry rode north, Shelby's men attacked, and they escaped to Fort Davidson. The 47th Missouri abandoned the fort and fought eastward, suffering about 30 captured or killed, and Shelby ordered Fort Benton burned. The Union reoccupied the fort by November 1864. By the end of 1864, companies of the 7th Kansas Cavalry manned the post, and on April 15, 1865, eight days after Gen. Robert E. Lee's surrender at Appomattox, they fought bushwhackers at nearby McKenzie's Creek in the last wartime action for the post. By the summer of 1865, the 7th Kansas had been reassigned to Nebraska.