At 1549 feet, Mount Tammany is one of New Jersey's highest mountains. It stands on the Jersey side of the Delaware Water Gap, and is part of the 40+ mile long mountain ridge known as the Kittatinnies.

The summit is easily gained by the Red Dot Trail, climbing from a rest area along westbound interstate 80 to the summit at a little over a mile. In late winter, while there is still some snow, the climb can be refreshing. Sparse winter growth allows for many fine views that are not available in summer, when vegetation limits visibility. Two particularly nice rock outcroppings adorn the Red Dot Trail, giving sweeping views of the Delaware Water Gap, and Mount Minsi in Pennsylvania. The first of these overlooks the rock formation known as Indan Head, where the dropoff to the highway, parking area, and Delaware River is quite sheer.

Because of its easy accesibility and proximity to both the New York City and Philadelphia metropolitan areas, Mount Tammany and the Red Dot Trail become quite crowded, even in late winter.