History of the Kansas City metropolitan area
The history of the Kansas City metropolitan area started in the 19th century as Frenchmen from St. Louis, Missouri moved up the Missouri River to trap for furs and trade with the Native Americans. The Kansas City metropolitan area, straddling the border between Missouri and Kansas at the confluence of the Kansas and Missouri Rivers, was a strategic point for commerce and security. Kansas City, Missouri was founded in 1838 and defeated its rival Westport to become the predominant city west of St. Louis. The area played a major role in the westward expansion of the United States. The Santa Fe, and Oregon trails ran through the area. In 1854, when Kansas was opened to Euro-American settlement, the Missouri-Kansas border became the first battlefield in the conflict in the American Civil War.
Kansas River
The mouth of the Kansas River in the West Bottoms area of Kansas City (at a longitude of 94 degrees 36 minutes West) was the basis for Missouri's western boundary from Iowa to Arkansas when it became a state in 1821 (Kansas entered the Union in 1861.) South of the Missouri River, that longitude still remains the boundary between Kansas and Missouri. North of the Missouri River, the state of Missouri extended its boundary further to the west in 1836 with the Platte Purchase. The river has moved slightly since this designation, but the state boundary has remained the same. This line is known as the Osage Boundary.