Statement of Significance (as of designation - April 19, 1994):
By tunneling through a 290-foot deep limestone ridge, Montgomery Bell created the first known water diversion tunnel in the United States; in fact, this is the oldest known full-size tunnel of any kind in the country. The tunnel, built between 1818 and 1819, served as a man-made water flume with an approximate 16 foot fall of water, which its owner planned to utilize as the central element of a water-powered industrial site. Bell's tunnel was almost certainly constructed using the long established method known as hand drilling, which utilized hand-held hammers, chisels, and black powder; the arduous labor was done by slaves.

Investigation revealed that the tunnel was not in danger of collapse.