The Gallery spans the entire length of the main house (excepting the servants' wing) and is approximately 90 feet long with a 14 ft ceiling height. It features a large marble fireplace, painted white pine paneling, and dentil crown molding. At the north end of the Gallery is the grand staircase that leads to the second story. Extending from the Gallery is the servants' wing, solarium, and the rest of the principal rooms. Above the fireplace hangs a portrait of Robert's father, Samuel Allerton (1828–1914), by Ellen Emmet Rand (1875–1941).