In that same year, Wentworth also granted to one Colonel John Hurd of Portsmouth, New Hampshire, part of the land which is today within the bounds of Monroe.

The grant was named "Hurd's Location" and included five small islands in the Connecticut River, known as "Deer Islands", and a parcel of land from below the present Village Bridge to the foot of Fifteen Mile Falls.

[4]: 63, 637 (map) The first known settlers on the "West Lyman" portion of Lyman were John Hyndman (also, "John Hinman"), with his wife and son, who settled on the largest of the Deer Islands (below the present-day Barnet Bridge) in 1784 and built a log cabin.

[4]: 33–34  The first native son, Ethan Smith, was born in a cabin on the Canaan Road (over the Gardner Mountain to Lyman) in 1784.

[6] "Captain"[7] Phillip Paddleford, a Revolutionary War soldier, settled in 1790, and built Monroe's first sawmill and gristmill on what is now called Smith Brook.

It was a covered bridge of pine, over 300 feet (91 m) long, and stood for over 96 years, making it one of the oldest on the river.

"Within the limits of the town are the narrows, at which place the Connecticut River is only five rods in width, being confined by walls of slate.

The dam, located on what was once called "Fifteen Mile Falls", is now used for flood control, irrigation and generation of electrical power for transmission to New England states.

At the time of its construction, it was the largest "retaining wall" in the United States, representing more than 90,000 cubic yards (69,000 m3) of concrete.

[4]: 110 Prior to the establishment of a series of dams, the river dropped 367 feet (112 m) in 15 miles (24 km), from Dalton to Bath.

[1] The town is bounded by the Connecticut River (which is also the state boundary with Vermont) to its west and the long ridge of Gardner Mountain to the east.

[4]: 110 NH 135 runs through the town, substantially parallel to the river, linking Monroe to Littleton to the north and Bath to the south.