Garvin's Falls is a historical site along the Merrimack River in Bow. The falls were named after John Garvin, who built a dam and a canal there in the early 1800s. The dam was used to power mills and factories, and the canal was used to transport goods and passengers. President James Monroe visited the falls in 1817 and rode on a canal boat. Today, the falls are mostly submerged by a hydroelectric dam, but they can still be seen at low water levels. The falls are part of the Upper Merrimack River.

The Merrimack River is a 117-mile-long river in the northeastern United States. It rises at the confluence of the Pemigewasset and Winnipesaukee rivers in Franklin, New Hampshire, flows southward into Massachusetts, and then flows northeast until it empties into the Atlantic Ocean at Newburyport. From the point where the Merrimack turns northeast in Lowell, Massachusetts onward, the Massachusetts–New Hampshire border is roughly calculated as the line three miles north of the river.