Atsion is on US 206 in Shamong, in the middle of Wharton State Forest, the largest single tract in the New Jersey state park system. The recreation area has a sand beach on Atsion Lake with a bathhouse, changing area, restrooms, showers, a first aid station and a concession stand, plus picnic tables and grills under the pines. Swimming is permitted only when lifeguards are on duty, generally 10:00 am to 6:00 pm daily during the summer season, and the beach closes to swimming outside those hours.

The water is the thing people remember. It runs the color of strong iced tea, stained by tannins leaching out of the Atlantic white cedars that line the Mullica River and its tributaries, and stained further by the bog iron in the sand. It is clean, it is soft, and you cannot see your feet in three feet of it. The lake is shallow and it warms up early, so the season here effectively starts before Memorial Day even though the guards do not.

The name comes from the ironworks. Atsion was a Pine Barrens bog iron town founded in 1766 by Charles Read, one of a string of furnaces and forges that smelted iron out of the bog ore deposits along the streams here and shipped cannonballs and stove plates out through the Mullica. The industry collapsed when Pennsylvania anthracite made bog iron obsolete in the mid nineteenth century. What is left standing is worth the walk: the 1826 Atsion Mansion built by Samuel Richards, a Greek Revival house with columns facing the highway, plus the church, the store and several workers' cottages. Joseph Wharton assembled the whole area in the late 1800s with a plan to pipe Pine Barrens water to Philadelphia; New Jersey blocked it, and the state bought his holdings in 1954.

Entrance fees are collected in season, $5 weekday and $10 weekend for New Jersey residents, $10 and $20 for out of state vehicles. The campground on the far side of the lake has tent and trailer sites and rental cabins, and there are separate group sites. The Batona Trail, a 50 mile sand path across the Pine Barrens, passes within a couple of miles, and the Mullica River Trail runs downstream from Atsion toward Batsto Village, the better preserved of the two ironworks sites and about eight miles south on Route 542.

Paddling out of Atsion is excellent. The Mullica above and below the lake is a narrow, slow, cedar shaded creek that a beginner can handle, and liveries in Vincentown and Chatsworth run shuttles on it. Bring bug spray in June. The Pine Barrens is also one of the darkest places on the east coast, which makes the campground unexpectedly good for stargazing.