Fort Ord is a former United States Army post on Monterey Bay on the Pacific Ocean coast in California, which closed in 1994 due to Base Realignment and Closure (BRAC) action. Most of the fort's land now makes up the Fort Ord National Monument, managed by the United States Bureau of Land Management as part of the National Conservation Lands, while a small portion remains an active military installation under Army control, designated the Ord Military Community.

Before construction and official designation as a fort in 1940, the land was used as a maneuver area and field-artillery target range beginning in 1917. Fort Ord was considered one of the most attractive locations of any U.S. Army post, because of its proximity to the beach and California weather. The 7th Infantry Division was its main garrison for many years. When Fort Ord was later converted to civilian use, space was set aside for the first nature reserve in the United States created for conservation of an insect, the endangered Smith's blue butterfly. Additional endangered species are found on Fort Ord, including Contra Costa goldfields and the threatened California tiger salamander.

While much of the old military buildings and infrastructure remain abandoned, many structures have been torn down for anticipated development. California State University, Monterey Bay (CSUMB) and Fort Ord Dunes State Park, along with some subdivisions, the Veterans Transition Center, a commercial strip mall, a recreational skydiving facility, military facilities, and a nature preserve occupy the area today.

On April 20, 2012, President Barack Obama signed a proclamation designating a 14,651-acre (5,929 ha) portion of the former post as the Fort Ord National Monument. In his proclamation, the President stated "The protection of the Fort Ord area will maintain its historical and cultural significance, attract tourists and recreationalists from near and far, and enhance its unique natural resources, for the enjoyment of all Americans."

After the American entry into World War I, land was purchased just north of the city of Monterey along Monterey Bay for use as an artillery training field for the United States Army by the U.S. Department of War. The area was known as the Gigling Reservation, U.S. Field Artillery Area, Presidio of Monterey and Gigling Field Artillery Range. Although military development and construction was just beginning, the war only lasted for another year and a half until the armistice on November 11, 1918.

Despite a great demobilization of the U.S. Armed Forces during the inter-war years of the 1920s and 1930s, by 1933, the artillery field became Camp Ord, named in honor of Union Army Maj. Gen. Edward Otho Cresap Ord (1818–1883). Primarily, horse cavalry units trained on the camp until the military began to mechanize and train mobile combat units such as tanks, armored personnel carriers and movable artillery.

By 1940, the 23-year-old Camp Ord was expanded to 2,000 acres (810 ha), with the realization that the two-year-old conflict of World War II could soon cross the Atlantic Ocean to involve America. In August 1940, it was re-designated Fort Ord and the 7th Infantry Division was reactivated, becoming the first major unit to occupy the post. Sub-camps were built around the Fort to support the new training of Troops, Camp Clayton. Camp Clayton was built near CA Highway 1, the South Dakota National Guard 147th Artillery were the first unit to train at the new camp.

In 1941, Camp Ord became Fort Ord. Soon the first threat came from the west as the Imperial Japanese Navy struck the island of Oahu, Hawaii at Pearl Harbor near Honolulu in an unannounced air attack, Sunday, December 7. In a few days the other Axis powers, such as Adolf Hitler's Nazi Germany, along with Fascist Italy of Benito Mussolini, declared and spread war in Europe against Great Britain, France and the Low Countries to the U.S.