Jean Baptiste Point DuSable made a trading post on the north bank of the Chicago River in the late 1780s. Fort Dearborn followed on the opposite side in 1803–1804. South Water Street, along the south bank, became a hub of activity in the 1830s, with Lake Street, a block to the south, soon picking up the character of a retail street. In the period of the walking city the Loop area accommodated all of the functions of the city near the main stem of the river.
The Chicago fire in 1871 destroyed most residential buildings, as well as historic church and school buildings, in the heart of the city. The rise of the skyscraper in the 1880s reinforced the trend toward commercial growth, creating a distinct character for the downtown district and establishing a skyline as the symbol for the entire city.