Barton Hills Village is not actually part of Ann Arbor, but a separate village adjacent to the northwest side of Ann Arbor. According to its website, the community was created by Detroit Edison in 1913; the company bowed out in 1940, and the Village was chartered in 1973.
Barton Hills has the highest per capita income of any locality in Michigan - as of the 2000 census, its 335 occupants had a per capita income of $110,683. (Yes, per person, not per household.)
Residents of Barton Hills Village are all in Ann Arbor, MI 48105 for postal service. The village is within Ann Arbor Township.