About 1890 the army engineers planning new defenses of San Francisco Bay proposed to build two mortar batteries on a tract of land between Laguna de la Merced (Lake Merced or, more properly, Lake of Mercy) and the Pacific Ocean, in the southwestern corner of San Francisco. The Spring Valley Water Company, owner of the yet undeveloped land, was amenable to a 'friendly' condemnation suit, and in this manner the government acquired in December 1900 roughly 45 acres at $900 per acre, and established the Lake Merced Military Reservation. However no construction took place until World War I provided the stimulus, when in February 1917 the Engineers commenced building a temporary battery for four 12-inch mortars, with the guns for it to come from Batteries Stotsenburg-McKinnon, Pits 3 and 4. The battery is significant because of its unusual straight line configuration (a result of the practical difficulties of having four crews working simultaneously in a four mortar pit), and because it was the very last mortar battery in service in the United States
Battery Howe apparently retained its mortars until 1945, this "temporary" battery thus far outlasting the armament of many "permanent" mortar batteries Today, however, nothing remains of Battery Walter Howe. It was destroyed when the City of San Francisco expanded it water treatment facilities to the north of the old fort.