Lee's Summit is a city in the state of Missouri, and is contained within the counties of Jackson (primarily) and Cass. As of the 2010 census found the population at 91,364 making it the sixth-largest city in the Kansas City Metropolitan Area and the sixth-largest city in Missouri. In 2006 CNN/Money and Money magazine ranked Lee's Summit 44th on its list of the 100 Best Cities to Live in the United States.