431 First St., SE, 11, 15, 21 Rock Glen, 507, 511, 525, 541 E. State St., 22, 28, 110, 120, 204, South Carolina Ave. 56,, Mason City, Iowa. County/parish: Cerro Gordo.
Added to the National Register of Historic Places April 26, 2016. NRIS 16000196.
9 contributing buildings. 3 contributing sites. 2 contributing structures. 2 contributing objects.