The first colonist to settle in present-day Monson was Ian Farry, who in 1657 was granted 200 acres (81 ha) of land by the Massachusetts General Court.

He built a tavern along the Bay Path, which was the primary route from Springfield to Boston, and which ran through the northern part of Monson.

It was the first house built between Springfield and Brookfield, but the tavern was short-lived; within a year or two, Fellows abandoned it for fear of attacks from local Native Americans.

The town was named after Sir John Monson, president of the British Board of Trade and a friend of Massachusetts governor Thomas Pownall.

One of the most successful industries during this time was the woolen mills, which were operated by industrialists such as Joseph L. Reynolds, Dwight W. Ellis, C. W. Holmes, and S. F. Cushman.

It was used for a short time by the federal government to supply stone for the Springfield Armory, and was later sold to Rufus Flynt, who opened a commercial quarry on the site in 1825 with five employees.

[6] The majority of the town (the center part) is drained to the north by Chicopee Brook, a tributary of the Quaboag River.

Small areas of the northeastern part of town flow to Foskett Mill Stream, a tributary of the Quaboag.

Monson is bordered on the north by Palmer, on the east by Brimfield and Wales, on the south by Stafford, Connecticut, and on the west by Hampden and Wilbraham.

Among its graduates were abolitionist and suffragist Lucy Stone, and two United States Supreme Court justices: William Strong and Henry Billings Brown.

US Route 20 forms part of the northern border with Palmer, and also cuts across the extreme northeastern corner of the town.