Which Apartment in Manhattan Is the Furthest Away from a Subway Station?

If you live in the heart of a major city, easy access to public transportation is essential. In New York City, that priority includes the subway system. If you live in Manhattan, how far away from you is the nearest subway station?
Ben Wellington, an instructor in city planning and statistics at the Pratt Institute, is the person to ask. He operates I Quant NY, a blog about geographical and statistical analyses of New York City. Recently, he searched for the apartment in Manhattan that is the furthest away from a subway station. That apartment is the penthouse suite of 10 Gracie Square. It's 0.8 miles away from a subway entrance.