Rocks State Park
The King and Queens Chair Loop trail at Rocks State Park is consistently one of the top hikes in Maryland. From the view at the top, I can understand why!
You can make the hike as long or short as you want. We chose to park at the Park Office and hiked along the white trail and the red trail which ended up being about 3 miles, and took us about 2 hours. There are some steep parts along the white trail, so I'd consider it as moderate difficulty.
The cool part about the trail is not only the grand view at the top, but the history. The "King and Queen Seat" was a ceremonial location for the Susquehannock Indians, according to legend. Tourists came to this location in the 1800s, and you can see carvings into the rock.
If you park at the Rock Ridge Picnic area, there are play areas for kids. You can take the red trail from there to the King and Queen Seat.