The Daniel Webster Law Office and Library, also known as Daniel Webster Law Office, is a National Historic Landmark on the grounds of the Isaac Winslow House at 64 Careswell Street in Marshfield, Massachusetts. The office was built in 1832 for Daniel Webster as part of his expansive Marshfield estate. It housed part of his collection of law and agricultural books, and served as a retreat from the main house. It was designated a National Historic Landmark in 1974, and is listed on the National Register of Historic Places.[1]