Mill River Union High School, commonly known as Mill River or MRU is a public junior-senior high school in Clarendon, Vermont. and is part of the Mill River Unified Union School District. MRUUSD includes the towns of Clarendon, Wallingford, Shrewsbury and Tinmouth. Other towns whose students attend Mill River include Ira, Middletown Springs and Danby.The current principal is Tyler Weideman.The current superintendent of the district is Dave Younce.