Keokuk, Iowa, served as a Civil War staging and training ground for seven Union regiments, with the first soldiers mustered at Camp Ellsworth in May 1861 and later camps Rankin, Halleck, and Lincoln preparing Iowa troops for deployment south. Its location on the Mississippi River made Keokuk an important Union Army hospital center, and the first wounded arrived soon after the Battle of Shiloh in Tennessee on April 7, 1862. Patients continued to arrive throughout the war, and military hospitals operated at the College of Physicians and Surgeons, Simpson House, Rice's Hardware Store, and the public school, while the largest facility, the Estes House, was converted from a hotel into a U.S. General Hospital that treated sick and wounded troops from April 17, 1862, until October 1, 1865. Soldiers who died in Keokuk military hospitals were first buried in an Oakland Cemetery lot, which the city donated after the war to the federal government for expansion into Keokuk National Cemetery. By 1871, the 2.5-acre cemetery held 627 Union dead, only twenty-seven unknown, and also contained the graves of eight Confederate prisoners of war who died in Keokuk. By that year, an iron fence enclosed the cemetery, upright cannon flanked the entrance, a Second Empire-style brick lodge for the superintendent and his family was complete, and four artillery pieces on gun carriages encircled a new flagstaff, while a summer house offered visitors a place to rest and contemplate. In 1912, the Woman's Relief Corps and the State of Iowa erected a 30-foot-tall granite pedestal topped by a granite statue of a Union soldier, dedicated to unknown soldiers buried in the cemetery, after the state legislature appropriated $2,000 the previous year. Sometime after 1929, the cornerstone of the Estes House Hotel was placed in the cemetery as a memorial to soldiers who died in Keokuk's U.S. General Hospital during the Civil War.