A quick Google search for “one-year master’s in history” yielded a couple results.
Brandeis (http://www.brandeis.edu/departments/history/grad/ma.html)
Brown (http://www.brown.edu/academics/history/graduate/master-arts-ma) - their professional track might especially apply
William & Mary (http://www.wm.edu/as/history/gradprogram/maearlyamerican/index.php)
George Washington, possibly (http://www.gwu.edu/masters-programs)