Southwick was originally inhabited by either the Matitacooke, Mayawaug, or Woronoake Native American tribes.

In the mid-17th century, pioneering English explorers moving up the Connecticut River Valley in search of fertile farmlands and game discovered the area and settled Southwick.

It became a farming community, defined as the Southern (South-) village (-wick) part of the town of Westfield.

Its first residential home was built by Samuel Fowler and his wife Naomi Noble on what is now College Highway (US 202 and MA 10), approximately one-quarter mile (0.4 km) north of the current town center.

The southernmost portion of Southwick joined Suffield, Connecticut, as the result of a simultaneous secession of citizens in that part of the village.

A border dispute continued until 1804 when the current boundary was established through a compromise between Connecticut and Massachusetts.

Due to winter freezing, summer drought, and wildlife impact (beaver dams, etc.

Laflin-Phelps Homestead was built soon after the area was settled and remains the oldest standing structure in Southwick.

With the railroad came the ice industry and tourist resorts around the Congamond Lakes (which were named Wenekeiamaug by the previous native peoples).

There was a special stop near the lakes where visitors would disembark to swim and/or pile into canopied pleasure boats.

It has been noted that local girls would gather letters thrown by the soldiers from the train and forward them to the intended recipients at the post office.

Babb's Roller Skating Rink on the Suffield side of Congamond Lakes is all that remains of the amusement park.

The farmland of Southwick is well-suited to grow tobacco,[2] which is widely grown as a cash crop.