Peirce Crosby (January 16, 1824 – June 15, 1899) was a rear admiral in the United States Navy, whose active duty career included service in the Mexican–American War and the Civil War. Early life and career Born in Upper Chichester Township, Delaware County, Pennsylvania, Crosby is a descendant of John Morton, signer of the U.S. Declaration of Independence. Crosby was appointed midshipman in June 1838. He reached the rank of Lieutenant in September 1853 after a decade and a half in ships of the Home and Mediterranean Squadrons, plus coast survey duty. He served in the sloop-of-war and the schooner in the Mexican–American War, and had shore assignments in and around Philadelphia, Pennsylvania. From late 1853 until the outbreak of the Civil War in the spring of 1861, Lieutenant Crosby served in the sloops of war , of the Brazil Squadron, and , and on board the receiving ship at Philadelphia. Civil War During April–October 1861, as the Civil War ran through its first half year, Crosby served in the sloop of war and briefly commanded the new gunboat . He went to the Gulf of Mexico as Commanding Officer of the gunboat at the beginning of 1862. In Pinola, assisted by , he broke the chain barrier across the Mississippi to make possible the passage upriver of Flag Officer David Farragut's squadron, and the capture of New Orleans. For two years beginning in November 1862, Crosby helped enforce the blockade of the Confederacy's East Coast as Commanding Officer of the steamers , and , and as Fleet Captain of the North Atlantic Blockading Squadron. He finished the war in the Gulf, commanding the gunboat , and took part in clearing mines from Mobile Bay. Post-Civil War activities Commander Crosby spent the first three years of the post-Civil War era in the south Atlantic as Commanding Officer of the gunboat . Following promotion to Captain in May 1868, he had a variety of shore assignments and, in 1872–1873, commanded the steamer . In 1877–1881, in the rank of Commodore, Crosby was commandant of the League Island (Philadelphia) Navy Yard. Flag assignments and retirement He finished his active career as a Rear Admiral, commanding the South Atlantic Squadron in 1882–1883 and the Asiatic Squadron later in 1883. In October of the latter year he was placed on the Retired List. Late in his life, Admiral Crosby served as the Assistant Secretary