The Casper and Abraham Shafer Grist Mill Complex is located at 928 Main Street in the village of Stillwater in Stillwater Township of Sussex County, New Jersey, United States.

[1] The listing also includes the Miller's House, built around 1800.

[3] In the early 1740s, Casper Shafer (1712–1784) built a dam across the Paulins Kill to provide power for a wooden grist mill near this site.

In 1764, he replaced it with a stone grist mill at this site.

The mill features a Leffel water turbine installed in 1893.