Ft. Miles was equiped with a variety of coastal defense and anti-aircraft guns, including 16" guns with 25 mile range, 12" guns with a range of 13 miles, and 155mm guns with a range of almost 12 miles, with similar guns emplaced in Cape May across the Delaware Bay. With a distance of 12 miles between Ft. Miles and Cape May, this provided a formidible defense to the entrance of the bay.