By sheer coincidence, "Gill" is the only full municipality of the 351 towns and cities currently administered in the Commonwealth of Massachusetts whose name has characters entirely in alphabetical order.

Prior to the arrival of English colonists, the Massachusetts portion of the Connecticut River valley was occupied by the Nipmuc, an Algonquin-speaking tribe.

A site on the river near the great falls shows evidence of human habitation dating back 10,000 years or more.

During King Philip's War in 1676, Captain William Turner led 150 colonists in an attack on this settlement, in which 100-200 Indians (mostly women, children, and elderly) were slain.

Elected officers were Moses Bascom Jr. as town clerk and treasurer, Moses Bascom, William Smalley and Noah Munn as selectmen and assessors, and David Squires as constable.

[5] Gill is located on the west bank of the Connecticut River, which flows along the town's eastern and southern edges.

The Fall River, a small tributary, forms the boundary with Greenfield to the southwest.

Continuing clockwise, the town shares land boundaries with Bernardston in the northwest, and a portion of Northfield to the north.