Lynnewood Hall is a 110-room Neoclassical Revival mansion in Elkins Park, Pennsylvania. Currently undergoing renovations after sitting nearly vacant for years, it was designed by architect Horace Trumbauer for industrialist Peter A. B. Widener and built between 1897 and 1900. Considered the largest surviving Gilded Age mansion in the Philadelphia area, it housed one of the most important Gilded Age private art collections of European masterpieces and decorative arts, which had been assembled by Widener and his younger son, Joseph E. Widener.

Horace Trumbauer was a prominent American architect of the Gilded Age, known for designing residential manors for the wealthy. Later in his career he also designed hotels, office buildings, and much of the campus of Duke University.