Mill River Union High School, commonly known as Mill River or MRU, is a public juniorsenior high school in Clarendon, Vermont. and is part of the Rutland South Supervisory Union. RSSU 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 Todd Finn  and the assistant principal is Tyler Weidman. The current superintendent of the district is Dave Younce.

Mill River competes in Division II in Vermont in all sports except football, where they compete in Division III. It competes in the local Marble Valley League (MVL).

  • The girls’ soccer team was ranked #1 in the state in 2004 and 2005.
  • The football team won the state championship in 1994
  • The girls’ basketball team won the state championship in 2015.

In 2008, both the boys’ and girls’ soccer teams won all of their games, as did the boys JV team in 1996.

In 2014, the baseball team won the state championship.

Mill River Union High School’s Music program is run by Kristin Cimonetti. Kristin conducts a senior choir of over seventy students and a junior choir of over forty students. Kristin also conducts four honors ensembles; the Chamber sings (bass and treble voices), the Clef Hangers (bass voices), the Tempo Tantrums (treble voices), Cantiamo (bass unchanged), Vivace (treble unchanged). Students who participate in the music program are accepted into the New England festival, All-State festival and District five music festivals annually.

Mill River’s theater company is Stage 40. This is run by a student board of directors. Each season it performs three shows, and helps the middle school (Stage 20) run a spring play. The 2007-2008 season included The Pirates of Penzance by Gilbert & Sullivan. The fall show was an adaptation of Roald Dahl‘s The Twits. The 2009-2010 season included Splendor in the Grass, by William Inge, based on the film of the same name, directed by Elia Kazan; Discourse on Dissent, a series of shorts based on war themes; and The Witches. The Middle school did a performance of Alice in Wonderland. Other productions have included, Sam Shepard’s Geography of a Horse Dreamer, Slavomir Mrozek’s, Fox Hunt, and Ted Hughes’, The Pig Organ.