The New Hampshire Archaeological Society has located over 30 Native American sites along the shore of the Merrimack River in Litchfield, with artifacts several thousands of years old being uncovered.

In 1656, William Brenton, colonial governor of Rhode Island, was granted land which included much of present-day Litchfield.

[6] In 1749, the land was granted to another group of settlers and named "Litchfield" after George Henry Lee, Earl of Lichfield.

Historically farmland, the town experienced steep population growth starting in the 1970s, along with the rest of southern New Hampshire, as a bedroom community and exurb for Greater Boston.

There is no bridge connecting Litchfield and Merrimack; the closest river crossings are to the south between Nashua and Hudson, and to the north between Manchester and Bedford.

There were 2,389 housing units at an average density of 160.1 per square mile (61.8/km2) accounting for actual land area available.

There are few remnants left, including a portion of rail trail and a dilapidated trolley bridge within Parker Park.

The state forest is managed by the New Hampshire Department of Natural and Cultural Resources, among other agencies.

The Litchfield Mosquito Control District was featured on Last Week Tonight with John Oliver.

The episode featured segments from a televised town meeting from September 17, 2015, which had no members of the public in attendance.

[15][16] The town has several conservation areas, including Moore's Falls, Parker Park, and Stage Crossing.

The Litchfield Conservation Commission holds the responsibility of managing these lands for the preservation and proper utilization of natural resources in town.