Kansas City is in two U.S. states: Missouri and Kansas. The larger and more famous Kansas City is in Missouri, while there is also a separate Kansas City just across the state line in Kansas.

Quick answer

  • Kansas City, Missouri (often called KCMO) is the biggest and best-known city with that name and is in the state of Missouri.
  • Kansas City, Kansas (often called KCK) is a smaller, separate city just over the border in the state of Kansas.
  • When people casually say “Kansas City” (NFL Chiefs, downtown, main skyline), they almost always mean the one in Missouri.

How the confusion started

  • The original city developed on the Missouri side along the Missouri and Kansas rivers and was eventually named Kansas City, Missouri.
  • A separate community grew on the Kansas side and incorporated later as Kansas City, Kansas, sharing the name but remaining a different city and government.

Today’s Kansas City area

  • The “Kansas City metro” is a single urban region that straddles the Missouri–Kansas border, with multiple counties in each state.
  • Missouri’s Kansas City is the largest city in Missouri, while Kansas’s Kansas City is one of that state’s larger cities but much smaller than its Missouri neighbor.

TL;DR: Kansas City is both in Missouri and in Kansas, but the main, larger Kansas City most people refer to is in Missouri.

Information gathered from public forums or data available on the internet and portrayed here.