Lexington, consolidated with Fayette County and often denoted as Lexington-Fayette, is the second-largest city in Kentucky and the 60th-largest city in the United States. By land area, Lexington is the 28th largest city in the United States. Known as the "Horse Capital of the World," it is the heart of the state's Bluegrass region. With a mayor-alderman form of government, it is one of two cities in Kentucky designated by the state as first-class; the other is the state's largest city of Louisville.[a] In the 2016 U.S. Census Estimate, the city's population was 318,449, anchoring a metropolitan area of 506,751 people and a combined statistical area of 723,849 people. Due to constant increases in population, Lexington suffers some of the worst traffic congestion in Kentucky, because two interstates bypass the city to the north and east, resulting in a lack of freeways (besides partial freeway New Circle Road) going through the most populated areas of the city.