900 Stewart Avenue is a building in Ithaca, New York, noted for its Egyptian Revival architecture, its dramatic placement partway down a cliff, and being the residence of astronomer Carl Sagan. The building is on a ledge about 50 feet (15 m) below street level, overlooking Fall Creek and Ithaca Falls. One of just two Egyptian Revival buildings in Tompkins County, along with the Masonic Temple in downtown Ithaca, it is part of the Cornell Heights Historic District.