The visibility here is usually good, although the silty bottom stirs up at the slightest touch. The usual diving area has a maximum depth of about 60 ft, although in other spots the reservoir is much deeper. Entry is a short hike down a grassy slope to a pebble beach. There is an underwater training platform, and often you will find an O/W class there. Water temps get up into the high 70's later in the season, although it is chilly below the 30 ft thermocline. The surrounding park is an exceptionally beautiful place, and many people go for swimming, fishing, picnicking, hiking and cycling. Unfortunately, compared to the ocean, Round Valley is a relatively dull dive. Mud, rocks, snails, and a few fish can be found, as well as huge stands of water plants later in the season. NJSCUBA.NET has very detailed info and nice photos on Round Valley.
Located by the town of Clinton, NJ in Round Valley State Park. About a 90 minute drive from NYC. About 40 minutes away from another popular local dive, Dutch Springs.