I've hiked the section from 355 to Watkins Mill Road several times (in both directions). There is a scenic overlook about 2 miles from 355 that's really fantastic in Winter, and quite pretty in summer. About 1/2 mile before you get to Watkins Mill Road, there's a gigantic boulder that goes over the stream and forms an interesting natural bridge. This trail gets a lot of use, so look out for bikes, runners and dogs.
I am reviewing the trail from Clopper Rd to 355. I parked on Frederick Rd and headed south towards Clopper Rd. First, if you follow the trail going right, it dead ends because you have to cross the creek, so unless you want to get your feet wet, you have to go onto the hard road and cross the bridge. Next, this section of the path is very overgrown and needs to be trimmed back, I found a deer tick on me so watch out for that. Also, part of the trail has been washed out by a small stream and there is a trail closed sign. Hikers have created a haphazard detour around this by finding a narrow point to hop across so you can get through, but I don't really recommend this particular section. It has a lot of noise from traffic and is not very peaceful at all. I have gone the other way on this trail from the parking lot and that was a much more enjoyable experience
I did this trail probably 4 to 5 times, ones alone or with my friend Ricky and Harold we are from Peru and this trail doesn't have many reviews so will see I started at the Seneca park at clopper rd then I hiked all to route 28, it took 4 hours on a slow pace, sometimes just watching the scene and listening to the woods.
I saw some dears and ducts along the trail where sometimes there is a river along the trail. One I hiked from the Potomac river to route 28 and was nice too i have seen the trail on summer. autumn fall and winter. It's also good to run but no bikes along the trail not permitted and the park police are always at the park. The lake is very nice too, I have seen people kayaking and fishing once. And is kid friendly watch for poison and once I brought my Doberman.
The park it self it's good with tons of space to walk, nice picnic tables with grill.
There are very nice trees on one of the picnic areas rarely seen.
Started at RT 355 and hiked to Black Rock Rd Mill, about 9 miles. Nice trail. Easy to follow as it is well blazed. Very wide open trail through Seneca State Park section and passes right through the Frisbee Golf area of the Park. Some sections before and after the Park were fairly weedy with lots of poison ivy to be wary off, but the weeds weren't too bad; the trail is open through them. Only a few other hikers on the trail today even though it was Saturday of Memorial Day weekend. At Riffleford Rd there were at least 12 cars parked and a large group of about 35 well-dressed people. I believe they were getting ready to do an immersion baptism, but I didn't hang around to watch. Shortly after passing that road, there were lots of wild strawberries along the trail. I ate a lot of them but did leave a few for anyone following along behind. The trail has very little elevation change and follows the creek pretty closely most of the way. The section just before Black Rock Road was particularly scenic with a few swimmers frolicking in the stream. The section between Rt. 118 and Black Rock Road had the most elevation change with a few small climbs before dropping back down to follow the creek to old Black Rock Mill. At the top of the first climb after Rt. 118 was a nice little pine forest. There is no parking or even a pull off area along Rt. 118 as guard rails hug both sides of the road with only a cut-through for the trail to pass through on both sides. Saw very little wildlife along the way, only a chipmunk, couple of squirrels, and one hawk. The mountain laurel along the trail at the power cut going into Seneca State Park was at its prime and gorgeous. Would like to thru-hike this 26 mile trail end to end at some point on a one or two night overnight, ending at the Potomac River.