Greater Boston is the metropolitan region of New England encompassing the municipality of Boston, the capital of the U.S. state of Massachusetts and the most populous city in New England, and its surrounding areas. The most stringent definition of the region consists of most of the eastern third of mainland Massachusetts, excluding the Merrimack Valley and most of Southeastern Massachusetts, though most definitions include much of these areas and portions of southern New Hampshire.

Boston, officially the City of Boston, is the capital and most populous city in the Commonwealth of Massachusetts in the United States. The city serves as the cultural and financial center of the New England region of the Northeastern United States. It has an area of 48.4 sq mi (125 km2) and a population of 675,647 as of the 2020 census, making it the third-largest city in the Northeast after New York City and Philadelphia. The Greater Boston metropolitan statistical area, including and surrounding the city, is the largest in New England and eleventh-largest in the country.