Explore Andalusia Historic House & Gardens during guided house tours and self-guided garden tours every Monday and Tuesday, April through October (closed holidays). A National Historic Landmark located just north of Philadelphia, the Big House at Andalusia provides an unparalleled look into our nation's past and serves as one of the finest examples of Greek Revival architecture in the country. Stroll the spectacular formal gardens and native woodlands at your leisure, and enjoy sweeping views from the banks of the Delaware River.