Lemon Hill (1800–01) is a Federal-style mansion in Fairmount Park, Philadelphia, built by the merchant Henry Pratt. Originally part of Robert Morris's 300-acre (120 ha) estate, The Hills, Pratt purchased 43 acres (17 ha) at a sheriff's sale for $14,654 in 1799. According to Pratt's letterbooks, recently discovered by Philadelphia Museum of Art assistant curator Martha C. Halpern, he designed the mansion himself and served as his own general contractor.