If you are looking for an outing near to home, try the Black Rock Mill located right in the middle of Seneca State Park and Greenway Trail. It is a good place for exploration adjacent to Black Rock Road between Route 28 and Germantown Road.
In 1760, a tract of land on Seneca Creek, known as “Black Rock,” was deeded to John Brisco. In 1815, Thomas Hilleary built the Black Rock Grist & Saw Mill on a portion of that land called “Sprained Ankle Tract”.
Nicholas D. Offutt purchased the Mill in 1861 and operated it until his death in 1890. The mill remained in the Offutt family into the 1920s.
In 1973, the Maryland Forest and Park Service (DNR) purchased the land and added it to Seneca State Park. The mill required major renovations. Over the next seven years, improvements were made to stabilize the interior. The roof was removed and the rotted wood from inside the mill was lifted out through the open roof. Metal grates were installed in the windows, and the frame of a gabled roof was installed, along with a sack hoist.
Inside the walls of the now roofless old building are displays which tell the history of this grain-grinding mill. Featuring reinstalled gears and machinery, the displays give a cut-away view of the milling operation and describe how the mill functioned.
Many years ago, there was a steady supply of water coming from a dam situated 200 feet upstream. The dam does not exist anymore although startlingly high-water marks can still be seen on the inner portion of the walls marking the magnitude of the floods which have ravaged the Great Seneca valley over the last century. The 50-yard channel that provided water for the mill wheel still exists.
The interior partitions, made of black rock quarried across Seneca Creek, remain. Visitors can see “1815” engraved on the stone wall. This was a three-story stone structure with millstones on the second floor. Bags of raw grain and corn were lifted by pulley to the upper level. The grain was then poured down funnels and chutes to the millstone grinder.
In the renovation a ramp was installed to provide access to the second floor for a better view of the interpretive displays, and an inoperable metal wheel was affixed to one of the exterior walls.
Discover the Seneca Ridge Trail (Red) and Greenway Loop, a moderately challenging 3.5-mile loop trail. You need not make the loop, just follow the trail for half of your intended hike and turn back. This is a popular trail for hiking and running, but you can still enjoy some solitude during quieter times of day.