The river divided the city into three districts: north, south, and west. The first city charter officially recognized these districts. The boards of public works, police, and assessors all consisted of representatives selected from each of these divisions. Beginning with the ward system established in that charter, and periodically redrawn in following decades, the river continued to serve as one of the major boundaries between representative legislative districts in the city. The y-shape on today's city seal memorializes the original three districts.

Creator: State of Illinois
Source: Chicago Historical Society (ICHi-34562)