During the westward expansion, forts were built along the trails to provide protection for travelers and traders. These frontier forts played major roles in the history of the American West.

Fort Leavenworth
You can equate the beginning of Kansas with Leavenworth. The French first scouted this area, establishing a military post called Fort de Cavbagnial in 1744, where they traded with the local Indians, the Kansa, the Osage and the Delaware. Other tribes weren’t quite as friendly, as rumors of Indian attacks on settlers spread eastward. So Colonel Henry Leavenworth came to the fort with 188 soldiers to solve the “problems.” As a result, the first US military fort west of the Mississippi now sits on the bluffs of the Missouri. The town grew as an adjunct to the fort.

Fort Scott
Fort Scott was established in 1842 on the Marmaton River just west of the border of Missouri to protect the Indian Frontier. It was used as a supply depot, and troops participated in missions of exploration, served as escorts in the far West and participated in the Mexican War.

The US Army abandoned Ft. Scott in 1853 because most of the Indians were being removed south and west. Then the buildings were sold in 1855 and the fort became part of the town Fort Scott.
more information available at http://www.nps.gov/fosc/ .

Fort Riley
In an 1843 expedition, Captain John C. Fremont, "The Pathfinder," camped at the junction of the Smoky Hill and Republican Rivers. He reported great numbers of elk, antelope and Indians. Most of the Indian tribes were friendly at the time, because settlers had not yet moved into the area.

Within a few years, however, the "Great Migration" along the Oregon Trail and trade along the Santa Fe Trail brought thousands of pioneers through the "Indian Territory", as Kansas was known back then. Indian war parties began raiding wagon trains as they traveled through the bluffs of eastern Kansas. It became evident that military protection was needed for these pioneers. Thus began the chain of events leading to the founding of Fort Riley in 1852. At the time it was named Fort Center - because it was believed to be the geographical center of the country. In 1853, the post was renamed after Major General Bennett Riley.

Fort Riley stood as the major horse cavalry training school in our country and boasted a position as one of the best cavalry training schools in the world. The famous 7th Cavalry was put through harsh and difficult training before leaving for campaigns against Indians. From the gates of Fort Riley, the cavalry rode to such famous campaigns as: Beecher's Island, the Washita River Fight, and Battle of the Little Big Horn.

The First Infantry Division, more commonly known as the "Big Red One" - the "Fighting First" - came to Fort Riley from Germany in 1955 and remained in Kansas until 1995. Today Fort Riley is known as home of America's Army.

Fort Dodge
Fort Dodge was built in 1865 on the Santa Fe Trail near the Arkansas River. It served as a supply depot as well as a base for operations against the Plains Indians.

Fort Zarah
In 1864, Fort Zarah was built on the crossing of the Walnut Creek. It was one of a chain of forts built along the Santa Fe Trail to protect travelers. The fort was abandoned in 1869 and no traces of the old fort remain in its original location east of Great Bend.

Fort Harker
In 1865, Fort Harker was built to protect the Kansas Stage Line and military wagon trains traveling along the Smoky Hill Trail and the Fort Riley Road. It served as a supply depot and distribution point for all forts in Colorado, New Mexico, Arizona, and northern Texas.
Most of the Fort is privately owned, but Ellsworth County Historical Society manages the Fort Harker museum and grounds located in Kanopolis near the Smoky Hill River.

Fort Hays
Built in 1865 to defend travelers on the Smoky Hill Trail, which was a popular route for travelers to Denver and for a stagecoach line and mail service.

Fort Wallace
The was the most western military outpost in Kansas. Constructed in 1865, this fort was charged with protecting travelers on the Smoky Hill Trail. Troops were detailed from this fort to escort stagecoaches, express wagon trains, government officials and railroad workers.
The fort was abandoned in 1882. Part of the old post cemetery is all that is left of this historical fort near the present town of Wallace.