The Nahum Hardy House is a historic house at 724 Lexington Street in Waltham, Massachusetts. The 2+1⁄2-story wood-frame house was built c. 1845, and is a well-preserved local example of a Greek Revival side-hall house. It has a fully pedimented gable end, a full entablature with dentil-like peg moulding, and a single-story porch with Tuscan columns (probably a later addition). The corner boards are pilastered. The house stands on land purchased by Nahum Hardy from Harvard College in 1839.[2]