Mari-Castle is a historic summer estate at 41-43 South Main Street in Randolph, Vermont. Built in 1886 for Albert Brown Chandler, it was the town's finest summer house of the period, and was named for Chandler's wife Marilla. Chandler, president of the nationwide Postal Telegraph Company, was a Randolph native, who funded construction of the Chandler Music Hall. His estate, now used primarily for professional offices, was listed on the National Register of Historic Places in 1990.