Fort Carroll

 place with historical importance, abandoned / shut down, fortification, NRHP - National Register of Historic Places, American Civil War 1861-1865

This Third System fortification was begun in 1847. On October 8, 1850 the fort was officially named after Charles Carroll (1737-1832), a Maryland political leader and the last surviving signer of the Declaration of Independence.
As of 1851, it was intended to be armed with thirty-eight 42-pounder seacoast guns, seventy-six 32-pounder seacoast guns, thirty-three 24-pounder guns and twelve 8" heavy seacoast howizters, for a total of 159 guns.
The original design foresaw the fort being armed with some 225 cannon on three levels. However, in April 1861 at the outbreak of the Civil War, Fort Carroll's walls were still less than half the planned height of thirty feet. Only five gun platforms were ready and only two were armed with guns. Still, the Army emplaced about thirty cannon and manned the fort throughout the war. In April 1864 torrential rains flooded the fort’s magazines, which led the Army to move all the powder and ammunition to Fort McHenry.
It was modified for Endicott System concrete gun batteries constructed in 1900 (Batteries Towson, Heart and Augustin).
In March 1921, the Army officially abandoned Fort Carroll and moved all remaining military equipment to nearby Fort Howard.

It was listed on the National Register of Historic Places in 2015.