The town of Sac City was laid out in 1855 on the west bank of the Raccoon River, just above its juncture with Cedar Creek. The plan of the town is unusual for the Midwest. The center of the community is a large public square which is entered on the east or west by Main Street (US 20). The northern portion of this large public square is occupied by the Sac County Courthouse; to the south is City Hall and General Sherman Hall. The courthouse was designed by J. M. Russell, who had planned a similar courthouse at Storm Lake the year before (since destroyed). The Sac City building is a two-and-a-half-story brick and stone-trimmed building on a raised basement; it makes a minimal nod to the Richardsonian Romanesque. One enters the building through a stone-framed Richardsonian arched opening; each facade projects toward a central bay which rises to steeply pitched stone gables. The central tower that visually unified the design was removed in 1900.

On the west side of the river is a large public park containing the obligatory relocated log cabin (c. 1870) and an extensive six-sided park pavilion (c. 1900), open on the sides and rising in the center to a clerestory section.