Waco ( WAY-koh) is a city in and the county seat of McLennan County, Texas, United States. It is situated along the Brazos River and I-35, halfway between Dallas and Austin. The city had a U.S. census estimated 2022 population of 143,984, making it the 24th-most populous city in the state. The Waco metropolitan statistical area consists of McLennan, Falls and Bosque counties, which had a 2020 population of 295,782. Bosque County was added to the Waco MSA in 2023. The 2023 U.S. census population estimate for the Waco metropolitan area was 304,865 residents.