Black Rock is one of the main crossings on the Seneca (MD). Upstream looks pretty good.
Working upstream from the Riffle Ford parking area reveals a nice Maryland stream, but no trout.
Route 28 gives you good access to Great Seneca Creek allowing you to go up or downstream.
They stock at the Riffle Ford Road access point, but I came up dry when I fished it in March.
A good place to go right after stocking.
I was stunned to discover 16 miles of stocked trout water in GAITHERSBURG!