Boston is the capital and most populous city of the Commonwealth of Massachusetts in the United States and the 21st most populous city in the United States. The city proper covers 48.4 square miles (125 km2) with an estimated population of 692,600 in 2019, also making it the most populous city in New England. It is the seat of Suffolk County. The city is the economic and cultural anchor of a substantially larger metropolitan area known as Greater Boston, a metropolitan statistical area (MSA) home to a census-estimated 4.8 million people in 2016 and ranking as the tenth-largest MSA in the country. As a combined statistical area (CSA), this wider commuting region is home to some 8.2 million people, making it the sixth most populous in the United States.