Northwood State Park is located on route 4 in Northwood, New Hampshire. From the parking area, follow the dirt road past the metal gates. Shortly past the gates you will cross a stream. On the right side of road along the stream are the remains of a 19th century mill complex. While you explore the remains of the mill site, you might want to check out the Native American cairn site also found in the park (see map).

On the right side of road, where it crosses the stream, you will see an “L” shaped stone and earthen dam. The dam was built at the top of a moderate downward slope in the stream. (The mill complex took advantage of this drop in elevation to power the water wheel). The dam impounded water into a natural basin which can be viewed on the left side of the road. The dam was constructed with two heavy stone retaining walls with earth fill between them.

The mill building was built a short distance below the dam. The foundation was cut into a steep embankment. The foundation would have housed the machinery. Across the stream from the mill foundation is a long thick rectangular stone structure. Parallel to this structure is a retaining wall along the embankment of the stream. The purpose of this structure is not clear. It may have been part of the water wheel housing.

The upstream side of the mill dam.

The downstream side of the dam. Note the heavy stones used in the dam construction.

Cross-section of the dam showing the two heavy retaining walls on either side with earthen fill between them.

The mill foundation was cut into a steep embankment. The arrow points to the structure shown in the next photo.

A long thick rectangular stone structure in the stream across from the mill foundation.

This stone was found near the mill complex. It is approximately 6 feet in diameter by 5 inches thick.
The hole in the middle is 6 inches wide. The stone is not perfectly round therefore it is not a mill stone.
The purpose of this stone is a mystery.