The well kept 40'x 50', 3.5 story mill, of which the lower story is stone and 2.5 stories are brick, was built circa 1870 on a site that previously had other mills.

In 1812, a fulling mill run by Abe Zook was followed by, or converted into, a carding mill by Joseph Zook in 1824, who then sold to A. Schwartz in 1828. Soon after, it was known as Groff's Mill.

The inlet arch of the mill.

The flour, grist and corn meal mill operated with two turbines. No Headrace was needed due to the 4' dam's proximity to the Conestoga River, but a 12' tailrace issued the water back into the river.

The structure was a paper mill in 1864 owned by Emanuel Shroeber. A new 2 story 36'X 45', 2 story brick mill was constucted by B. W. Harnish or George Ehrhart in 1870.

It was converted to a grist mill and enlarged about 1875. Another story was added to the mill around 1870-85. The 1899 owner was J.K. Umble. The last owner was Christ J. Umble, ceasing operations early-mid. 20th century. The outlet arch, placed lower in the mill foundation than the inlet arch, is visible behind the sycamore tree trunk.

GPS: 40' 4.23N, 76' 15.7W 279'/85 meters Lancaster Quadrangle