Millers River, MA

The Millers River is a river in New Hampshire and northern Massachusetts, originating in Ashburnham, Massachusetts and Rindge, New Hampshire, joining the Connecticut River just downstream from Millers Falls, Massachusetts.

Millers River drains a total area of about 390 square miles (1,000 km2), about 313 square miles (810 km2) of which are in Massachusetts. Many wetlands in the basin indicate areas of former shallow lakes and ponds that have gradually been filled. There are a total of 107 lakes and ponds in the basin, 72 of which have an area of 10 acres (40,000 m2) or more. Only one lake, Lake Monomonac in Winchendon 592 acres (2.40 km2), is larger than 500 acres (2.0 km2) .

The North Branch and the main stem of the river join in Winchendon, and the river flows westward to the Connecticut River. Major tributaries of Millers River are the Otter River, which enters the Millers River in Winchendon in Otter River State Forest, and the Tully River, which enters the Millers River in Athol. Both tributaries flow mainly through wetlands. Overall, Millers River has a moderate gradient, averaging about 18 feet/mile from the headwaters area to the USGS streamflow-gaging station at Erving, a distance of about 43 river miles.

However, a 5-mile (8.0 km) reach of Millers River through a wooded area between South Royalston and Athol (the "Bear's Den") has an average gradient of about 43 feet/mile, which is about five times the average for rivers in Massachusetts, and some of the most rugged and steep terrain of the state's central upland. The gradient of the tributary Otter River averages about 18 feet/mile for a distance of about 11.5 river miles, and that of the East Branch Tully River, the major tributary of the Tully River, averages about 52 feet/mile over a distance of about 13 river miles.