During World War I, West Baden Springs Hotel became Army Hospital #35 as troops needing medical aid returned from war by the fall of 1918. The U.S. Army sought potential hospital sites across the country, and the hotel suited that purpose because of its healing waters, recreational opportunities, and rail access. The flu pandemic created a dire need for new army hospital facilities, so the hotel was quickly renovated and soon became known as US Army Hospital #35. Lillian Sinclair Rexford, daughter of Lee Sinclair, stayed there as a gracious host to wounded men and assisted in nursing soldiers back to health. Letters from soldiers housed there spoke fondly of Miss Lillian and the luxurious surroundings, and the posh setting was said to help lift the men's spirits. West Baden Springs Hotel served as the Army hospital until April 1919.