Sedgwick County (county code: SG) is a county located in the U.S. state of Kansas. As of the 2010 census, the population was 498,365, making it the second-most populous county in Kansas. The county seat is Wichita, the most populous city in the state.
The city of Wichita, Kansas had a population of less than 498,365 in 2010.
We know this because the city is in the county of Sedgwick, and in 2010, the entire county had a population of 498,365. So the population of Wichita must be less than that.