After the Civil War began in April 1861, it was apparent that the Fort at Clark's Point was still years from completion.

Fort Taber, a small earthwork with six cannons, was built nearby with city resources, and named after New Bedford's mayor during that period.

With new batteries being constructed under the Endicott program in 1898, the U.S. Army officially named the military reservation at the site and the fort as Fort Rodman Military Reservation, in honor of Lieutenant Colonel Logan Rodman, a New Bedford native with the 38th Massachusetts Infantry who died in the assault on Port Hudson, Louisiana in 1863.

[3] After the American entry into World War I many 5-inch guns were withdrawn from forts for potential service on field carriages on the Western Front.

However, Battery Cross's two guns were removed in 1917 and installed on the Army transport ship USAT Kilpatrick.

They were returned to Fort Rodman in March 1919, and scrapped in 1921 under a general removal from Coast Artillery service of 5-inch guns.

The 8-inch guns of Batteries Walcott and Barton were dismounted for potential service as railway artillery in June 1918, but were remounted later without leaving the fort.

[3] Battery Milliken was built 1917-1921 as part of a general upgrade of the Coast Artillery with existing 12-inch M1895 guns on new long-range carriages, initially in open mounts.

[3] Battery Milliken housed the post switchboard, and during World War II this was operated by the Women's Army Corps, for which the latrines were re-arranged.

[8] In 1938 a battery of two 155 mm guns on "Panama mounts" (circular concrete platforms) was built at Fort Rodman.

Several additional small-caliber batteries defended New Bedford and Buzzards Bay during World War II.

[3][4][6] Protecting the southern entrance to the Cape Cod Canal was a two-gun 155 mm battery on Panama mounts, replaced in 1943 by AMTB 934, at Butler Point Military Reservation in Marion.

The fort grounds and garrison buildings became a military reserve center, and eventually a wastewater treatment plant was built on part of the site.