Boston is the capital and largest city of the Commonwealth of Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is considered the economic and cultural center of the region, and is sometimes regarded as the unofficial "Capital of New England." Boston city proper had a 2007 estimated population of 608,352, making it the twenty-first largest in the country. Boston is also the anchor of a substantially larger metropolitan area called Greater Boston, home to 4.4 million people and the tenth-largest metropolitan area in the country. Greater Boston as a commuting region includes parts of Rhode Island, New Hampshire and Maine; it includes 7.4 million people, making it the fifth-largest Combined Statistical Area in the United States.
In 1630, Puritan colonists from England founded the city on the Shawmut Peninsula. During the late 18th century Boston was the location of several major events during the American Revolution, including the Boston Massacre and the Boston Tea Party. Several early battles of the American Revolution, such as the Battle of Bunker Hill and the Siege of Boston, occurred within the city and surrounding areas. Through land reclamation and municipal annexation, Boston has expanded beyond the peninsula. After American independence was attained Boston became a major shipping port and manufacturing center, and its rich history now attracts 16.3 million visitors annually. The city was the site of several firsts, including America's first public school, Boston Latin School (1635), and first college, Harvard College (1636), in neighboring Cambridge. Boston was also home to the first subway system in the United States.
With many colleges and universities within the city and surrounding area, Boston is a center of higher education and a center for medicine. The city's economy is also based on research, finance, and technology – principally biotechnology. Boston ranks first in the country in jobs per square mile ahead of New York City and Washington, DC. The city has been experiencing gentrification and has one of the highest costs of living in the United States, though it remains high on world livability rankings.
Owing to its early founding, Boston is very compact. According to the United States Census Bureau, the city has a total area of 89.6 square miles (232.1 km²)—48.4 square miles (125.4 km²) (54.0%) of land and 41.2 square miles (106.7 km²) (46.0%) of water. Boston is the country's fourth most densely populated city that is not a part of a larger city's metropolitan area. Of United States cities with more than 600,000 people, only San Francisco is smaller in land area.
Boston is surrounded by the "Greater Boston" region and is bordered by the cities and towns of Winthrop, Revere, Chelsea, Everett, Somerville, Cambridge, Watertown, Newton, Brookline, Needham, Dedham, Canton, Milton, and Quincy.
Boston's official elevation, as measured at Logan International Airport, is 19 ft (5.8 m) above sea level. The highest point in Boston is Bellevue Hill at 330 ft (101 m) above sea level, and the lowest point is at sea level.
Much of the Back Bay and South End neighborhoods are built on reclaimed land—all of the earth from two of Boston's three original hills, the "trimount," was used as landfill material. Only Beacon Hill—the smallest of the three original hills—remains partially intact; only half of its height was cut down for landfill. The downtown area and immediate surroundings consist mostly of low-rise brick or stone buildings, with many older buildings in the Federal style. Several of these buildings mix in with modern high-rises, notably in the Financial District, Government Center, the South Boston waterfront, and Back Bay, which includes many prominent landmarks such as the Boston Public Library, Christian Science Center, Copley Square, Newbury Street, and New England's two tallest buildings—the John Hancock Tower and the Prudential Center. Near the John Hancock Tower is the old John Hancock Building with its prominent weather forecast beacon—the color of the illuminated light gives an indication of weather to come: "steady blue, clear view; flashing blue, clouds are due; steady red, rain ahead; flashing red, snow instead." (In the summer, flashing red indicates instead that a Red Sox game has been rained out.) Smaller commercial areas are interspersed among single-family homes and wooden/brick multi-family row houses. Currently, the South End Historic District remains the largest surviving contiguous Victorian-era neighborhood in the U.S.
Along with downtown, the geography of South Boston was particularly impacted by the Central Artery/Tunnel (CA/T) Project (or the "Big Dig"). The unstable reclaimed land in South Boston posed special problems for the project's tunnels. In the downtown area, the CA/T Project allowed for the removal of the unsightly elevated Central Artery and the incorporation of new green spaces and open areas.
Boston Common, located near the Financial District and Beacon Hill, is the oldest public park in the U.S. Along with the adjacent Boston Public Garden, it is part of the Emerald Necklace, a string of parks designed by Frederick Law Olmsted to encircle the city. Franklin Park, which is also part of the Emerald Necklace, is the city's largest park and houses a zoo. Another major park is the Esplanade, located along the banks of the Charles River. Other parks are scattered throughout the city, with the major parks and beaches located near Castle Island; in Charlestown; and along the Dorchester, South Boston, and East Boston shorelines.
The Charles River separates Boston proper from Cambridge, Watertown, and the neighborhood of Charlestown. To the east lies Boston Harbor and the Boston Harbor Islands National Recreation Area. The Neponset River forms the boundary between Boston's southern neighborhoods and the city of Quincy and the town of Milton. The Mystic River separates Charlestown from Chelsea and Everett, and Chelsea Creek and Boston Harbor separate East Boston from Boston property
Boston has what may basically be described as something between a humid continental climate and a humid subtropical climate, such as is very common in coastal southern New England. Summers are typically warm and humid, while winters are cold, windy, and snowy. Prevailing wind patterns that blow offshore affect Boston, minimizing the influence of the Atlantic Ocean.
Spring in Boston can be warm, with temperatures as high as the 90s when winds are offshore, although it is just as possible for a day in late May to remain in the lower 40s because of cool ocean waters. The hottest month is July, with an average high of 82 °F (28 °C) and an average low of 66 °F (18 °C), with conditions usually humid. The coldest month is January, with an average high of 36 °F (2 °C) and an average low of 22 °F (−6 °C). Periods exceeding 90 °F (32 °C) in summer and below 10 °F (−12 °C) in winter are not uncommon but are rarely prolonged. The record high temperature is 104 °F (40 °C), recorded on July 4, 1911. The record low temperature is −18 °F (−28 °C), recorded on February 9, 1934. February in Boston has seen 70 °F (21 °C) only once in recorded history, on February 24, 1985. The highest temperature recorded in March was 89 °F (31 °C), on March 31, 1998.
The city averages about 43 in (108 cm) of precipitation a year, with 40.9 in (104 cm) of snowfall a year. Snowfall increases dramatically as one goes inland away from the city (Especially north and west of the city)—away from the warming influence of the ocean. Most snowfall occurs from December through March. There is usually little or no snow in April and November, and snow is rare in May and October.
Boston's coastal location on the North Atlantic, although it moderates temperatures, also makes the city very prone to Nor'easter weather systems that can produce much snow and rain. Fog is prevalent, particularly in spring and early summer, and the occasional tropical storm or hurricane can threaten the region, especially in early autumn.