Fort Riley  Fort Riley is a United States Army installation located in North Central Kansas, on the Kansas River, also known as the Kaw, between Junction City and Manhattan. The Fort Riley Military Reservation covers 101,733 acres (41,170 ha) in Geary and Riley counties. The portion of the fort that contains housing development is part of the Fort Riley census-designated place, with a residential population of 7,761 as of the 2010 census. The fort has a daytime population of nearly 25,000. The ZIP Code is 66442. Fort Riley is named in honor of Major General Bennet C. Riley, who led the first military escort along the Santa Fe Trail. The fort was established in 1853 as a military post to protect the movement of people and trade over the Oregon, California, and Santa Fe trails. In the years after the Civil War, Fort Riley served as a major United States Cavalry post and school for cavalry tactics and practice. The post was a base for skirmishes with Native Americans after the Civil War ended in 1865, during which time George A. Custer was stationed at the fort. In 1887, Fort Riley became the site of the United States Cavalry School. The famous all-black 9th and 10th Cavalry Regiments, the soldiers of which were called "Buffalo Soldiers", were stationed at Fort Riley at various times in the 19th and early 20th centuries. During World War I, the fort was home to 50,000 soldiers, and it is sometimes identified as ground zero for the 1918 Spanish flu pandemic, which its soldiers were said to have spread all over the world. Since the end of World War II, various infantry divisions have been assigned there. Most notably, from 1955 to 1996 the post was home to the famed 1st Infantry Division, also called "Big Red One". Between 1999–2006, the post was headquarters to the 24th Infantry Division (Mechanized) and known as "America's Warfighting Center". In August 2006, the Big Red One relocated its headquarters to Fort Riley from Leighton Barracks, Germany. Camp Whitside is named in honor of Brigadier General Samuel M. Whitside, who served as commander of Company B, 6th Cavalry Regiment, at Fort Riley, between the years of 1871 and 1874.  1st Infantry Division  Garrison  Partners  The early history of Fort Riley is closely tied to the movement of people and trade along the Oregon and Santa Fe trails.