Boylston Street is a major east–west thoroughfare in the city of Boston, Massachusetts and its western suburbs. The street begins in Boston's Chinatown neighborhood, forms the southern border of the Boston Public Garden and Boston Common, runs through Back Bay and Boston's Fenway neighborhood, merges into Brookline Ave and then Washington Street, emerging again contiguous with Route 9 out to where it crosses Route 128, after which it becomes Worcester Street.

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.