The town of Lynnfield was first settled in 1638 and was made a district separate from Lynn in 1782. It was later officially incorporated in 1814. Historically, Lynnfield functioned as two separate villages connected by one governing body: in Lynnfield Center resided a mostly agricultural population, while South Lynnfield was a crossroad situated amongst neighboring larger towns. During this time, the town had two inns, a granite rock quarry, a small carbonated beverage bottler, and various eating institutions.

The stagecoach line north from Boston to Portsmouth, New Hampshire, known locally as the “Newburyport Turnpike”, ran through South Lynnfield. Later this roadway became U.S. Route 1, the route which brought many people north to the small town during the post-World War Two population surge. Lynnfield had attractions such as horse shows and ballroom dancing. Lynnfield has since become a modern, chiefly residential suburb of Boston.

Along with the communities of Chelsea, Lynn, Salem, Marblehead, Danvers, Middleton, Andover, Methuen, Haverhill, Amesbury and Salisbury, Lynnfield was a part of “The Gerry-mander” so described by the Boston Gazette on March 26, 1812.

Lynnfield Center retained limited commuter rail service, via the Boston & Maine Railroad, into the late 1950s/early 1960s with a small railroad boarding platform located not far from the current Town Hall offices.

When, in the 1960s, the United States Post Office implemented the Zone Improvement Program with 5-digit numerical codes, Lynnfield was assigned two ZIP codes, 01940 and 01944, for the Lynnfield Center and the South Lynnfield post offices, respectively. Later, 01944 was reassigned to Manchester (now Manchester-by-the-Sea); South Lynnfield currently shares Zip Code 01940 with Lynnfield Center.

As of the census of 2010, there were 11,596 people, 4,179 households, and 3,267 families residing in the town. The population density was 1,143 people per square mile (439.5/km²). There were 4,354 housing units at an average density of 429.2 per square mile (162.7/km²). The racial makeup of the town was 94.7% White, 0.5% Black or African American, 3.3% Asian, 0% Pacific Islander, 0.4% from other races, and 1% from two or more races. Hispanic or Latino of any race were 1.7% of the population.

There were 4,179 households, out of which 35.2% had children under the age of 18 living with them, 68.5% were married couples living together, 7.1% had a female householder with no husband present, 2.5% a male householder with no wife present, and 21.8% were non-families. 18.8% of all households were made up of individuals, and 11.6% had someone living alone who was 65 years of age or older. The average household size was 2.77 and the average family size was 3.20.

In the town, the population was spread out, with 25.3% under the age of 18, 5.7% from 18 to 24, 19.6% from 25 to 44, 31.7% from 45 to 64, and 17.7% who were 65 years of age or older. The median age was 43 years. For every 100 females, there were 96.2 males. For every 100 females age 18 and over, there were 92.2 males.

The median income for a household in the town was $136,101, and the median income for a family was $95,804, which are both well over the national averages. Males had a median income of $82,386 versus $50,589 for females. The per capita income for the town was $50,916. The average household net worth is $966,273.

The town is more conservative than much of the state. In the 2012 Presidential election, former Governor Mitt Romney received 60.9% of the town’s vote. The 2012 results illustrates the town’s continued drift to the right. In the 2008 Presidential election, John McCain received 55% of the town’s vote, up slightly from the George W. Bush’s 53% in 2004.

Lynnfield uses the open town meeting model common in New England with a Board of Selectmen overseeing the operation of the town.

Lynnfield is part of Massachusetts’s 6th congressional district, represented by Seth Moulton, effective January 2015. In the Massachusetts Senate, Lynnfield lies within the Third Essex district and is currently represented by Democrat Thomas M. McGee. In the Massachusetts House of Representatives, the town is located within the 20th Middlesex district, represented by Republican Bradley Jones, Jr..