Kansas City, Missouri
Kansas City is the largest city in the U.S. state of Missouri. According to the U.S. Census Bureau, the city had an estimated population of 488,943 in 2017, making it the 37th most-populous city in the United States. It is the central city of the Kansas City metropolitan area, which straddles the Kansas–Missouri state line. Kansas City was founded in the 1830s as a Missouri River port at its confluence with the Kansas River coming in from the west. On June 1, 1850 the town of Kansas was incorporated; shortly after came the establishment of the Kansas Territory. Confusion between the two ensued and the name Kansas City was assigned to distinguish them soon after.
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.