21 East 81st Street 21 East 81st Street presents a rare and highly unique opportunity on one of the Upper East Side s most coveted townhouse blocks, perfectly positioned between Fifth and Madison Avenues. Built in 1899 by renowned architects Welch, Smith & Provot, this 20-foot-wide Neoclassical limestone townhouse spans approximately 8, 600 square feet across four stories, crowned by a mansard roof. Grand ceiling heights, significant original architectural detail, and wood-burning fireplaces in nearly every room define the interiors, while an elevator services all levels. Currently configured as a two-family residence an owner s triplex with a duplex rental apartment the home offers exceptional flexibility and long-term potential.