1827 Kansa Agency was established on the Kansas River, some four miles below the Grasshopper's (Delaware's) mouth. From up to 1838, this was the crossing point for "Sublette's Trace" travelers.
1829 Sublette's pack-train, en route West by way of Independence, Missouri for the first time traveled out the Santa Fe Trail some distance before turning northwest toward the Kansas river. This became the established Oregon-California trail route.
1830 William L. Sublette took the first wagons along the route (Oregon Trail) to the Rocky Mountains. 1842 Joseph and Louis Papin arrived and were probably the first white settlers at what is now Topeka. Papin's Ferry operated at the "Topeka" crossing of the Kansas (Kaw) River on the Oregon-California Trail until 1857 when a bridge was constructed. By the middle of the 1840s, traffic on the Oregon Trail was tremendous, and the California gold rush increased its use even more in 1849 and 1850.
1844 St. Joseph, Missouri branch of Oregon-California trail pioneered. Because of difficult terrain, and attempts to make the road less circuitous, the route was not a fixed one initially. Street's 1850 table of distances represents the established route.
[1844?] Before 1848 (and speculatively pioneered in 1844--the flood year) all Oregon-California trail cutoff routes over the hills left the main trail five miles east of the Little ( Red ) Vermillion Crossing, and it at the Big (Black) Vermillion.
1848 Fort Kearny established, at the head of Grand Island on the Platte. Its chief purpose: to protect the Oregon-California emigration.
1848 Union Town (Pottawatomie trading post) established. Many '49ers ferried or forded the Kansas at this new upper crossing, on the "Independence" Oregon-California Trail.
After 1849 the impact of gold discoveries in California caused the Oregon Trail to be labeled the California Trail by California-bound travelers.
The Oregon Trail continued to be heavily traveled during the Civil War, but as the Union Pacific Railroad was built, the use of the Oregon Trail declined.
Parts of the Oregon Trail were still used locally in 1870, but the Oregon Trail was no longer the great throughway it had been.