Merrimac is a small town located in Essex County, Massachusetts, in the northeastern region of the United States. It is situated on the north bank of the Merrimack River and is bordered by the towns of Amesbury to the east, West Newbury to the south, and Haverhill to the west.

The area that is now Merrimac was originally inhabited by the Pentucket tribe of the Pennacook Indians. The first European settlers arrived in the late 17th century, and the town was officially incorporated in 1876.

Today, Merrimac is primarily a residential community with a population of around 6,000 people. The town has a charming downtown area with a variety of small businesses, including restaurants, shops, and services. There are also several parks and recreational areas in town, including the Merrimac Town Forest and Lake Attitash, which offers boating and fishing opportunities.

Merrimac is located approximately 35 miles north of Boston and is easily accessible by Interstate 495 and Route 110. The town is also served by the Merrimac Public Schools system, which includes an elementary school and a middle school. High school students attend Pentucket Regional High School, which is located in nearby West Newbury and serves students from several surrounding towns.