Kansas City, Missouri, abbreviated KC or KCMO, is the largest city in the U.S. state of Missouri by population and area. It is located on the Missouri River at its confluence with the Kansas River, within Jackson, Clay, Platte and Cass counties. It is the 38th-most populous city in the United States and sixth-most populous city in the Midwest, with a population of 508,090 at the 2020 census. The Kansas City metropolitan area, which straddles the Missouri–Kansas state line, is the 31st-most populous metropolitan area in the nation, at 2.25 million residents.

Kansas City was founded in the 1830s as a port on the Missouri and Kansas rivers. On June 1, 1850, the town of Kansas was incorporated; soon afterwards, a region designated as the Kansas Territory was established. Confusion between the city and the territory of Kansas ensued, so the name Kansas City was assigned to distinguish the city from the territory. Sited on Missouri's western border with Kansas and with downtown near the rivers' confluence, Kansas City, Missouri encompasses about 319.03 square miles (826.3 km²), making it the 25th-largest city by total area in the United States. It is one of Jackson County's two seats along with the major satellite city of Independence; and Kansas City's other major Missouri suburbs include Blue Springs, Lee's Summit, Raytown, and Liberty. Kansas City Missouri's major Kansas suburbs include Overland Park, Olathe, Lenexa, and Kansas City, Kansas.

The city is composed of several neighborhoods, including the River Market District, 18th and Vine District, and the Country Club Plaza. Celebrated cultural traditions include Kansas City jazz; theater, as a historical center of the Vaudevillian Orpheum circuit in the 1920s; the nickname City of Fountains; the Chiefs and Royals sports franchises; and cuisine such as Kansas City–style barbecue and strip steak.

The town of Kansas, Missouri, was incorporated on June 1, 1850, reincorporated and renamed City of Kansas on March 28, 1853, and renamed Kansas City in 1889. The area straddles the border between Missouri and Kansas at the confluence of the Kansas and Missouri rivers, and was considered a good place to settle.

The Antioch Christian Church, Dr. James Compton House, and Woodneath are listed on the National Register of Historic Places.

In past centuries, the area's tribal inhabitants include the Hopewell tradition, Mississippian culture, Kansa, Osage, Otoe, and Missouri. The first documented European visitor to the eventual site of Kansas City was Étienne de Veniard, Sieur de Bourgmont, who was also the first European to explore the lower Missouri River. Criticized for his response to the Native American attack on Fort Détroit, he had deserted his post as fort commander and was avoiding French authorities. Bourgmont lived with a Native American wife in a village about 90 miles (140 km) east near Brunswick, Missouri, where he illegally traded furs.

To clear his name, he wrote Exact Description of Louisiana, of Its Harbors, Lands and Rivers, and Names of the Indian Tribes That Occupy It, and the Commerce and Advantages to Be Derived Therefrom for the Establishment of a Colony in 1713 and The Route to Be Taken to Ascend the Missouri River in 1714. In the documents, he describes the junction of the "Grande Riv[ière] des Cansez" and Missouri River, as the first adoption of those names. French cartographer Guillaume Delisle used the descriptions to make the area's first reasonably accurate map.

The Spanish took over the region in the Treaty of Paris in 1763, but were not to play a major role other than taxing and licensing Missouri River ship traffic. The French continued their fur trade under Spanish license. The Chouteau family operated under Spanish license at St. Louis, in the lower Missouri Valley as early as 1765 and in 1821 the Chouteaus reached Kansas City, where François Chouteau established Chouteau's Landing.