John A. Dahlgren

John A. Dahlgren
Dahlgren during the American Civil War
Birth name	John Adolphus Bernard Dahlgren
Nickname(s)	"Father of American naval ordnance"
Born	(1809-11-13)November 13, 1809 Philadelphia, Pennsylvania, U.S.
Died	July 12, 1870(1870-07-12) (aged 60) Philadelphia, Pennsylvania, U.S.
Buried	Laurel Hill Cemetery, Philadelphia, Pennsylvania, U.S.
Allegiance	United States (Union)
Service / branch	United States Navy
Years of service	1826–1870
Rank	Rear admiral
Commands	South Atlantic Blockading Squadron South Pacific Squadron Bureau of Ordnance Washington Navy Yard
Battles / wars	American Civil War
Spouse(s)	Madeleine Vinton Dahlgren
Relations	John Vinton Dahlgren (son) Ulric Dahlgren (son) Charles G. Dahlgren (brother)

John Adolphus Bernard Dahlgren (November 13, 1809 – July 12, 1870) was a United States Navy officer who founded his service's Ordnance Department and launched significant advances in gunnery.

Dahlgren devised a smoothbore howitzer, adaptable for many sizes of craft and shore installations. He then introduced a cast-iron muzzle-loading cannon with vastly increased range and accuracy, known as the Dahlgren gun, that became the U.S. Navy's standard armament.

In the Civil War, Dahlgren was made commander of the Washington Navy Yard, where he established the Bureau of Ordnance. In 1863, he took command of the South Atlantic Blockading Squadron at the rank of rear admiral. He helped William Tecumseh Sherman secure Savannah, Georgia.