If you've done much caching in Montgomery County Maryland, you are likely to have come across the sites of some of the more than 20 mills that once operated along its many streams. This cache will bring you to one of those mill sites.
At the given coordinates you will find an historical marker. With information from this sign you can obtain the coordinates for a cache hidden nearby at
N 39° 3.ABC' W 77° 1.DEB'
A = the last digit in the year that the mill burned
B = the last digit in the year Francis Valdenar purchased the mill
C = the third digit in the year that George Kemp bought the mill
D = the last digit in the year that Aaron Dyer bought the mill
E = the number of letters in the first name of the Quaker minister who originally owned the mill at this site
The cache is in a fairly obvious spot, but may be a little difficult to get to as it's guarded by briars. The cache container has a leash which you might want to look for to make retrieval a little easier. Some natural tools in the area may be helpful in putting it back as found.
There is an unactivated FTF trackable for the first to find.