Fort Kearny was a fort constructed during the American Civil War as part of the defenses of Washington, D.C. Located near Tenleytown, in the District of Columbia, it filled the gap between Fort Reno and Fort DeRussy north of the city of Washington. The fort was named in honor of Maj. Gen. Philip Kearny of the Union Army, who was killed at the Battle of Chantilly on September 1, 1862. Three batteries of guns supported the fort, and are considered part of the fort's defenses.

Philip Kearny Jr. was a United States Army officer, notable for his leadership in the Mexican–American War and American Civil War. He served in French Emperor Napoleon III's Imperial Guard at the Battle of Solferino.