Jersey City Reservoir No. 3 is a decommissioned reservoir atop Bergen Hill in the Heights of Jersey City, Hudson County, New Jersey, United States, situated on approximately 13.8 acres (5.6 ha) just south of Pershing Field. It was built between 1871 and 1874 as part of the city's waterworks system designed to provide potable water to the city, including Ellis Island. Its perimeter wall is in the Egyptian Revival style and pump stations are in the Romanesque Revival style. The reservoir provided drinking water until the 1980s, when it was drained and abandoned for a larger reservoir at the Boonton Gorge. Since that time, a mini-ecosystem has taken root time behind the thick, 20-feet tall stone walls including trees, wildflowers, swans, great blue heron, peregrine falcons, and at its center,