A river in Maryland rising in Carroll County and emptying into Chesapeake Bay.

(Mon: dp. 1,875; l. 241’; b. 46’; dph. 11’10"; dr. 11’1"; s. 6 k.; cpl. 105; a. 1 15" D.sb., 150-pdr. P.r.)

The fourth Patapsco, an ironclad monitor, was built by Harlan and Hollingsworth, Wilmington, Del.; launched 27 September 1862; and commissioned 2 January 1863, Comdr. Daniel Ammen in command.

Assigned to the North Atlantic Blockading Squadron, Patapsco participated in an attack on Fort McAllister at Savannah 3 March 1863. Moving to the North Edisto River in April, she sailed for Charleston on the 5^th to participate in the assault on that city’s defenses. Under almost continuous fire during the remainder of April and in July and August, she continued to operate against the forts in Charleston Harbor, and on 8-9 September she supported the storming of Fort Sumter. Through the fall of 1863 and 1864, she remained off that South Carolina city, engaged in the general attacks on the harbor’s defenses.

On the evening of 15 January 1865, however, while covering picket boats dragging for torpedoes (mines), Patapsco hit a torpedo and sank in less than a minute, taking 62 of her crew with her.