The Mill River is a tributary of the Connecticut River arising in the western hilltowns of Hampshire County, Massachusetts. It is notable for dropping in elevation, along with its West Branch, more than over . History Before European settlement, the Mill River was called Cappawonganick by the Nonotuck people. Dozens of mills were built along the Mill River in the early to mid 19th century to take advantage of the available waterpower. To maintain sufficient summer water flow four reservoirs were built in the higher tributaries of the river. Mill River Flood of 1874 In 1865, a group of mill owners from Williamsburg, Haydenville, Leeds, and Florence constructed a dam on the Mill River north of the town of Williamsburg, using a design drawn by one of the owners, a man with no engineering training. The dam was poorly constructed and leaked as soon as it was filled. On May 16, 1874, the dam failed catastrophically, killing 139 people in the towns to the south. The flood destroyed much of the villages of Williamsburg, Skinnerville, and Haydenville in the town of Williamsburg, and the village of Leeds in the town of Northampton. As high as the death toll was, it would have likely been much higher but for the actions of dam keeper George Cheney, who rode his horse at a gallop to Williamsburg to raise the alarm as the dam began to fail. Other riders took off from Williamsburg and were able to warn residents in towns to the south. Despite an inquest and the clear negligence of the mill owners, no one was punished in court for the disaster. Today, the former site of the Williamsburg Reservoir is accessible by a public hiking trail. This flood was widely covered in contemporaneous newspapers across the United States. The Great Flood of 1936 In the two weeks that elapsed between March 9 and March 22, 1936, two record-breaking storms showered the eastern United States in heavy rainfall. From Virginia to Maine, towns and cities in river basins all along the east coast experienced extensive flooding. A survey undertaken by the United States Geographical Survey the following year estimated that between 150 and 200 people were killed as a result of the floods. The same report tallied material damages in the hundreds of thousands. The monumental nature of the 1936 flood, along with another massive flood in 1938, led to the