THE UNITED STATES ARMY COAST ARTILLERY CORPS
During the 1880s the Endicott Board, which was headed by Secretary of War William Endicott, made significant recommendations for the improvement of coast defense fortifications and weapon systems. The board recommended a $127 million program for building new forts with breech-loading cannons and mortars at 29 locations on the US coast.
At the start of the 1900’s, the military realized that heavy (fixed) artillery had very different training requirements than the lighter mobile field artillery. This resulted in the Artillery Corps being divided into two new branches: Field Artillery and Coast Artillery. This process began in February 1901 with the formation of 126 companies of heavy (coast) artillery and 30 companies of light (field) artillery.
In 1907, the artillery was split into a Field Artillery, with a regimental organization, and the Coast Artillery Corps (C.A.C.), with additional Coast Artillery companies for a total of 170 companies.
During WWI many soldiers of the Coast Artillery saw duty overseas in railway and field artillery batteries.
Between WWI and WWII the C.A.C. focused on antiaircraft artillery (AA). The larger guns at the coastal forts were still used for training but were almost completely useless against aerial bombardment from enemy aircraft.
Most units were deactivated in the years 1944-1946 with the Coast Artillery Corps being inactivated on January 1, 1950.