The masonry shell of the Colt Gun Mill is an important remnant of the nation's first planned industrial community. When built by the Patent Arms Manufacturing Co. in 1836, the mill stood four-and-a-half stories tall, was topped with a bell tower capped by a gun-shaped weather vane, and surrounded by a fence with pickets shaped like a wooden gun. Now, through a combination of demolition and arson, only dilapidated brownstone walls remain. The mill produced revolvers until 1842, and subsequently manufactured silk and cotton. Its last owner was Allied Textile Printing (ATP), which closed the mill in 1983.

The mill sits on a prominent 7-acre site within the 90-acre Great Falls/S.U.M. National Historic District. The district comprises a manufacturing center started in 1792. The early industrialists situated their mills to take advantage of the Passaic River and its Great Falls. Since 1988 the site has been listed as a Priority One threatened National Historic Landmark in the U.S. Department of the Interior's Annual Report to Congress.

With its presence as a ruin preserved, the Colt Gun Mill will become the setting for an outdoor museum on waterpower, since the chronology of the Gun Mill's power source--from waterwheel to steam to electricity--mirrors the evolution of American industry. The Trust grant will fund stabilization of the ruin's four walls. The adaptive reuse of the mill is one phase of an overall site redevelopment that will include commercial and residential uses, project being directed by the National Park Service and the City of Paterson.