A Cruiser built for the Navy at the beginning of the 20th century, the USS Milwaukee was named after the largest city in the State of Wisconsin, as a consequence of being sponsored by one of that state's senators at the time, John Mitchell.

The Milwaukee (C-21) was laid down July 30th, 1902 by Union Iron Works, in San Francisco, California, and completed September 10th, 1904. In December of 1906, the ship was officially commissioned and her command was given to Commander Charles A. Grove.

After a shakedown off the coast of California and Mexico in the spring of 1907, USS Milwaukee departed San Francisco, and cruised the coast of San Salvador and Costa Rica protecting American interests and engaging in target practice with the squadron in Magdalena Bay before returning to her home port.

In March of 1908, the cruiser sailed from San Francisco for Bremerton, Washington, where she was placed in reserve. Except for a cruise in the summer of 1908, which took her to Hawaii and to Honduras, the ship remained in reserve status at Puget Sound Navy Yard until decommissioned in May 1910.

The USS Milwaukee was recommissioned and was assigned to the Pacific Reserve Fleet in 1913. Over the next 2 years the ship made several brief cruises, one to Honolulu, with a detachment of Washington State Naval Militia, and several along the coast of California. In March of 1916, Milwaukee was detached from the Reserve Fleet and assigned duty as tender to destroyers and submarines of the Pacific Fleet. Based at San Diego, the cruiser participated in exercises and maneuvers off the coast, patrolled Mexican waters, transported refugees, and performed survey duty.

After an overhaul at Mare Island late in 1916, USS Milwaukee sailed for Eureka, California, to assist in salvaging U.S. submarine H-3 which had run aground in Humboldt Bay. On the 13th of January, while attempting to float the submarine, the cruiser stranded in the first line of breakers at Samoa Beach off Eureka. The crew reached shore safely, but attempts to salvage the ship were unsuccessful.

USS Milwaukee was decommissioned March 6th, 1917 and a storm in November 1918 broke the ship in two. Her name was struck from the Navy list in June 1919 and her hulk was sold for scrap later that summer.