Longmeadow was first settled in 1644, and officially incorporated October 17, 1783. The town was originally farmland within the limits of Springfield. It remained relatively pastoral until the street railway was built c. 1910, when the population tripled over a fifteen-year period. After Interstate 91 was built in the wetlands on the west side of town, population tripled again between 1960 and 1975.

During the 19th and early 20th centuries, Longmeadow was best known as the site from which Longmeadow brownstone was mined. Several famous American buildings, including Princeton University’s Neo-Gothic library, are made of Longmeadow brownstone. In 1894, the more populous and industrialized “East Village” portion of the town containing the brownstone quarries split off to become East Longmeadow.

Designed by famed golf course architect Donald Ross in 1922, the Longmeadow Country Club was the proving ground for golf equipment designed and manufactured by the Spalding Co. of Chicopee. Bobby Jones, a consultant for Spalding, was a member in standing at LCC and made a number of his instructional films at LCC in the 1930s.

Longmeadow is located in the western part of the state, just south of the city of Springfield, and is bordered on the west by the Connecticut River and Agawam, to the east by East Longmeadow, and to the south by Enfield, Connecticut. It extends approximately 3 miles (5 km) north to south and 4 miles (6.4 km) east to west. It is approximately 20 miles (32 km) north of Hartford.

More than 30% of the town is permanent open space. Conservation areas on the west side of town include more than 750 acres (3.0 km²) bordering the Connecticut River. The area supports a wide range of wildlife including deer, beaver, wild turkeys, foxes, and eagles. Springfield’s Forest Park, which at 735 acres (2.97 km²) is the largest city park in New England^{[citation needed]}, forms the northern border of the town. The private Twin Hills and public Franconia golf courses, plus town athletic fields and conservation land, cover nearly 2/3 of the eastern border of the town. Two large public parks, the Longmeadow Country Club, and three conservation areas account for the bulk of the remaining formal open space. Almost 20% of the houses in town are in proximity to a “dingle”, a tree-lined steep-sided sandy ravine with a wetland at the bottom that provides a privacy barrier between yards^{[citation needed]}.

Longmeadow has a town common, commonly referred to as “The Green”^{[citation needed]}, located along U.S. Route 5 on the west side of town. It is about 0.5 miles (0.80 km) long. Roughly 100 houses date back before 1900, most of which are in the historic district, are located near the town green. Longmeadow’s Town Green is a historic district on the National Register of Historic Places, and it is surrounded by a number of buildings dating back to the 18th and 19th centuries. Longmeadow is unique as the town green has maintained its residential purpose and has resisted commercial pressure. The current function as listed by the National Register of Historic Places is domestic and landscape. The current sub-function as listed by the National Register of Historic Places is park and single dwelling. Houses along the photogenic main street (Longmeadow Street) are set back farther than in most towns of similar residential density.^{[citation needed]}The town has three recently remodeled elementary schools, two secondary schools, and one high school. The commercial center of town is an area called “The Longmeadow Shops”^{[citation needed]}, including restaurants and clothing stores.

According to the United States Census Bureau, the town has a total area of 9.7 square miles (25.0 km²), of which 9.1 square miles (23.6 km²) are land and 0.50 square miles (1.3 km²), or 5.34%, are water.

As of the census of 2000, there were 15,633 people, 5,734 households, and 4,432 families residing in the town. The population density was 1,732.5 inhabitants per square mile (668.9/km²). There were 5,879 housing units at an average density of 651.5 per square mile (251.5/km²). The racial makeup of the town was 95.42% White, 0.69% African American, 0.05% Native American, 2.90% Asian, 0.06% Pacific Islander, 0.26% from other races, and 0.62% from two or more races. Hispanic or Latino of any race were 1.09% of the population.

There were 5,734 households, out of which 37.1% had children under the age of 18 living with them, 69.1% were married couples living together, 6.4% had a female householder with no husband present, and 22.7% were non-families. 20.4% of all households were made up of individuals, and 14.0% had someone living alone who was 65 years of age or older. The average household size was 2.66 and the average family size was 3.09. [Citation needed]

In the town, the population was spread out, with 26.8% under the age of 18, 4.6% from 18 to 24, 22.0% from 25 to 44, 28.7% from 45 to 64, and 17.8% who were 65 years of age or older. The median age was 43 years. For every 100 females, there were 87.7 males. For every 100 females age 18 and over, there were 82.0 males. [Citation needed]

The median income for a household in the town was $109,586, and the median income for a family was $115,578. Males had a median income of $68,238 versus $40,890 for females. The per capita income for the town was $48,949. About 1.0% of families and 2.1% of the population were below the poverty line, including 0.3% of those under age 18 and 8.3% of those age 65 or over^{[citation needed]}.

The town is chartered as an Open Town Meeting form of government. The town government also consists of a Select Board with five members, elected by the town. The public school system is governed by the School Committee. The School Committee is made up of seven voting members elected by the town, the superintendent of schools, two assistant-superintendents, a secretary, and a student representative.