Stephen Clegg Rowan was born near Dublin, Ireland, of Protestant parents, and was named for his maternal grandfather. His father's name was John Rowan. Having been severely burned at an open fire in a Wexford hotel, where the family stopped en route to America, Stephen was left with his grandparents, and was ten years old when he joined his parents, brother, and sisters at Piqua, Ohio.
He studied at Oxford, Ohio.
Rowan was appointed a midshipman in February 1826, while studying at Oxford, and made his first cruise on the Vincennes, 1826-30. This sloop was the first American man-of-war to circumnavigate the globe. After two years at New York on a revenue-cutter, he spent four years in West Indies waters as passed midshipman and master on the schooner Shark and the sloop Vandalia. The Vandalia received news of the Dade massacre, at Pensacola, hurriedly provisioned the ship for three months, and sailed for Florida to cooperate in the Seminole War. Rowan subsequently commanded dangerous boat expeditions on the Withlacoochee River, in Charlotte Harbor, and on Miakka River.
He was promoted to the rank of lieutenant in 1837 and the following year was ordered to the coast survey. He served from 1841 to 1844 in the Delaware on the Brazil and Mediterranean stations, and in July 1845 became executive officer of the Cyane on the Pacific Station. News of imminent war with Mexico reached the squadron at Mazatl n, and the Cyane, under Capt. S. F. Du Pont, proceeded to Monterey where it cooperated with Commodore Sloat in the capture of the city on July 7, 1846. Rowan was ordered to build earthworks, blockhouse, and stockade, a task which would have presented unlimited difficulties for many a seaman, but which he accomplished quickly and effectively. He was then ordered to take a detachment of marines and seamen and occupy San Diego where the Cyane blockaded the port until provisions were exhausted. She later sailed for San Francisco and then returned to San Diego, where Rowan, commanding a battalion of seamen and marines, joined the army under Stockton and Kearney. He fought in the battles, Rio San Gabriel and the Mesa, and helped to retake Los Angeles.
Later at Mazatlan, he led a boat expedition to San Jose to relieve Lieutenant Heywood's detachment, besieged by Mexicans and nearly starved. During the ten years following the Mexican War, he served two tours of duty as ordnance inspector at the New York navy yard, commanded the supply-ship Relief, and the receiving-ship North Carolina. He was made commander on September 14, 1855. At the beginning of the Civil War, he was in command of the steam-sloop Pawnee, which supplied the chief defense of Washington during Lincoln's inauguration, and cooperated in the unsuccessful attempts to relieve Fort Sumter, and to burn the Norfolk navy yard.
In May 1861 he directed against the batteries at Aquia Creek the first shot fired from a naval vessel in the war. The Pawnee joined Stringham's squadron in August and helped to capture two forts and about 600 men at Hatteras Inlet.
He assisted the army, on March 14, to capture New Bern, taking seven small forts mounting thirty-four guns. He was promoted to the rank of captain on July 16, 1862, and the same day, as a reward for his gallantry, was made a commodore. He next commanded the New Ironsides, South Atlantic Blockading Squadron, and was under fire fourteen times in Charleston harbor from July 18 to September 8, 1863, being struck 164 times. In August 1864, he was detached to command for two months all naval forces in North Carolina sounds and he was then placed on waiting orders. On July 25, 1866, he was promoted to rear admiral. He was in command of the Norfolk navy yard, 1866-67, Asiatic Squadron, 1867-70; and the New York navy yard, 1872-76; governor of the Naval Asylum at Philadelphia in 1881, superintendent of the Naval Observatory in 1882, and president of various important naval boards. He was commissioned vice admiral on August 15, 1870, and retired in 1889.
He died at the Ebbitt House, Washington, D. C. , and was buried in Oak Hill Cemetery, Georgetown, beside his wife.
Rowan was prominent for his military campaigns during the Mexican War and the war in the United States from 1861 to 1865. He took an active role serving as executive officer of the sloop Cyane during the capture of Monterey, California on 7 July 1846, and in the occupation of both San Diego and Los Angeles. Rowan's most distinguished service was rendered on February 8, 1862, when, commanding a flotilla of nondescript vessels in the North Carolina sounds, he cooperated with General Burnside in the capture of Roanoke Island and destruction of a Confederate gunboat. The next day he made a dashing attack at Cobb's Point on the Pasquotank River, destroyed the fort and captured or routed the Confederate squadron, and took both Elizabeth City and Edenton.
Rowan was married to Mary Stark, born in Norfolk, Va. Their only child who lived was Maj. Hamilton Rowan of the United States Army.
