The city hall building, designed by Henry Austin, was built in 1861; the old courthouse building, now an annex, designed by David R. Brown, was built in 1871–73.

The pair of buildings was listed on the U.S. National Register of Historic Places in 1975.

They are significant early examples of High Victorian Gothic architecture in the United States.

The city hall building's most striking feature used to be a clock tower that rose above.

In January 2012, a PureCell Model 400 was dropped into place behind City Hall in the Millennium Plaza.