Named for Brigadier General Daniel Webster Flagler, Fort Flagler was one of five fortifications built in the Puget Sound area at the turn of the 20^th century. These posts were established to prevent a hostile fleet from reaching the Bremerton Naval Yard and to provide protection for developing cities in the area.

The fort’s purpose was primarily defense, but these shores never saw any action. Soldiers spent their time here training for battles overseas, keeping up the grounds, and competing in friendly games like baseball.

The fort evolved many times throughout periods of war and peace. During times of peace the fort was put into caretaker status to save costs. In 1937, the Army realized that the neglected buildings had rot and mold caused by frequent rain, so many of the original structures were demolished. In 1941, the fort saw a quick renovation, in preparation to the United States’ anticipated entry into World War II, with the construction of mobilization buildings to once again house soldiers. These structures were meant to be temporary, but most have lasted more than 70 years.

During the early 1900s, technology saw rapid advancements. By 1938, most of the 26 original guns had either been removed or scrapped. Many were removed during WWI to be converted into railway artillery for use in Europe; two of the 10-inch guns were sent to Canada. The guns currently located at Battery Wansboro were brought from Fort Wint in the Philippines to put on display.

Following WWII, the Army sent amphibious units at Fort Flagler, Fort Worden, and Fort Casey to use the beaches for amphibious training. These forts, at Admiralty Inlet, were meant to be the base for the West Coast amphibious units, but the United States’ entrance into the Korean Conflict changed this. Fort Flagler was decommissioned shortly after, in 1953. The State of Washington purchased the property in 1955 and designated it a State Park.