Lake Oscawana is located at the heart of Putnam Valley, New York, United States. The 386-acre lake has a depth that ranges from 25 to 30 feet at its deepest. The lake is fed by a stream from its north end and it drains out into Oscawana Creek at the middle of its southeastern shore. It is located between two hill ranges. Oscawana Creek merges into Pe…Lake Oscawana is located at the heart of Putnam Valley, New York, United States. The 386-acre lake has a depth that ranges from 25 to 30 feet at its deepest. The lake is fed by a stream from its north end and it drains out into Oscawana Creek at the middle of its southeastern shore. It is located between two hill ranges. Oscawana Creek merges into Peekskill Hollow Creek near the intersection of Peekskill Hollow Road and Oscawana Lake Road in Putnam Valley the hamlet of Lake Peekskill.