Black Moshannon State Park sits about eight miles east of Philipsburg on the Allegheny Plateau, just west of the Allegheny Front, at roughly 1,900 feet of elevation. The swimming is at a sand beach near the north end of 250 acre Black Moshannon Lake, a reservoir held back by a dam on Black Moshannon Creek. The Civilian Conservation Corps built the original dam starting in 1933, it was replaced in the 1950s, and the current Kephart Dam dates from 1974. The beach runs roughly 440 feet of shoreline, with a CCC era beach house, a picnic shelter, restrooms and drinking water set just behind the sand, and day use parking immediately beyond that.

The water is the color of strong tea, and that is natural rather than a sign of pollution. Clear springs and small streams feed the lake after passing through the sphagnum bogs that surround it on nearly every side. Peat and wetland plants steep tannins into the water, which is where the black in the park's name comes from. DCNR describes the bog as working like a giant teabag. Expect to lose sight of your feet well before waist depth. The bottom at the beach is sand and shelves gradually.

No lifeguard works this beach. Pennsylvania runs nearly all of its state park beaches on an open swim basis, which means you swim at your own risk while park staff patrol rather than guard. Presque Isle and Fuller Lake at Pine Grove Furnace are the only two exceptions in the state. The park's posted season is mid-May to mid-September, 8:00 AM to sunset, and swimming is limited to the buoyed area. The beach is ADA accessible and a beach wheelchair can be requested. Smoking is banned on the sand and in the swimming area, including cigars, pipes and e-cigarettes, with separate areas provided alongside. Staff sample the water and will close the beach when bacteria counts climb. That happened for close to a month in the summer of 2021 after heavy rain, with goose droppings a large part of the problem, and sampling went from weekly to daily until the counts dropped.

Getting in costs nothing. DCNR charges no entrance fee and no day use fee at any Pennsylvania state park, and the lake beach is free to use. What DCNR does charge for is anything you reserve: campsites, the cabins, and mooring permits, of which the lake has 87 spaces across four launch and mooring areas. Boat rental is seasonal and runs through a concession. Gas motors are prohibited on the lake, leaving electric only at slow no wake speed, so the swimming area stays quiet.

The Bog Trail boardwalk leads out over the wetland responsible for the water's color. Seventeen orchid species grow in and around the bog, along with all three carnivorous plants native to Pennsylvania. The 1,592 acre Black Moshannon Bog Natural Area was set aside in 1994. Cool air pooling in the shallow basin at this elevation supports leatherleaf, Canada warblers and other species more usual farther north. Loons, mergansers and tundra swans pass through on migration, and beavers and muskrats work the shoreline. Moshannon State Forest, more than 43,000 acres of it, wraps around the park's 3,394 acres.