Historically it served as the headquarters for city and township government as well as holding the offices of numerous state, local and national entities.

The two-story Italianate structure features several decorative elements and an 1863 Civil War cannon on its lawn.

The building currently houses the historical society's Flagg Township Museum, with artifacts and exhibits about the area's history.

Disagreements over the project eventually led to the city of Rochelle's refusal to pay its share and, thus, construction was delayed indefinitely.

Election day in Rochelle and official polling places were established in 1885, both decisions were made within the walls of the City and Town Hall.

[2] The first floor's north facade is adorned with two double-hung windows with projecting segmented arch crowns and stone sills.

Also on the north facade is the original main public entry door and an arched transom window.

[2] On the rear (south) facade is an attached one story structure that housed the men's jail cells.

All of the jail building's windows and doors feature arched brick crowns, a theme repeating from the two-story portion of the structure.

[2] The period of greatest significance for the City and Town Hall is 1885–1942, between those years the building housed numerous governmental and political entities, at the local, state and national levels.

In 1972, the Illinois Historic Sites Survey Inventory cited the building for its significance in two areas, architecture and education.

The May 1972 survey form stated that its use as a public building from 1884 to 1970 and its current use as a museum justified its significance in these areas.