On July 24, 1915, the Eastland, along with the Theodore Roosevelt and the Petoskey, were hired to take employees from Chicago's Western Electric Company to a picnic in Michigan City, Indiana. Passengers began boarding around 6:30 AM. By 7:10, the ship had reached its capacity of 2,500 passengers. It had also developed a list to the port, which the crew attempted to stabilize by admitting water to the ballast tanks. The tug Kenosha was preparing to maneuver Eastland away from the dock, but by 7:28, the Eastland began to roll over, coming to rest in 20 feet of water only 20 feet from the wharf. The Kenosha came alongside the hull to allow passengers to leap to safety. 841 passengers and 4 crew died in the disaster. This can be compared to the sinking of the Titanic in 1912 with a loss of 829 passengers (but 694 crew).

After the Eastland was raised in October 1915, she was sold to the Illinois Naval Reserve and recommissioned as the USS Wilmette stationed at Great Lakes Naval Base . On June 7, 1921, the Wilmette was given the task of sinking the UC-97 , a German U-Boat captured during World War I. The guns of the Wilmette were manned by Gunner's Mate J.O. Sabin , who had fired the first American shell in World War I, and Gunner's Mate A.F. Anderson , the man who fired the first American torpedo in the conflict.

In 1946, the Wilmette was offered up for sale. Finding no takers, the government sold her for scrap and she was demolished in 1947.