Waller Hall is a building on the campus of Willamette University in Salem, Oregon, in the United States. Opened in 1867 as University Hall, it is the oldest higher-education building west of the Mississippi River still in use, currently housing the university's administrative offices. Built in the Renaissance style of architecture, it was added to the National Register of Historic Places in 1975. The building has been gutted twice by fires with the interior rebuilt each time, and went through renovations in 1987 to 1989 and again in 2005.