Who ruled Chicago?

Chicago stands on the south-western shore of Lake Michigan, where a sluggish river once wandered through marsh into the lake. Its importance comes from geography: only a low, swampy divide separated the Chicago River, which drains to the Great Lakes and the Atlantic, from the Des Plaines and Illinois rivers, which flow to the Mississippi. Whoever controlled this short portage linked two of North America's great water systems. In the 19th century canals and then railways turned that advantage into explosive growth, and a frontier trading post of a few hundred people became, within sixty years, a city of more than a million.

The area was home to Native peoples for thousands of years, from Hopewell-era mound builders to the Miami, Illinois and, by the 18th century, the Potawatomi. The city's name comes from a local word for a wild onion or leek that grew along the river. In 1673 the French explorers Louis Jolliet and Jacques Marquette crossed the portage on their way back from the Mississippi, and the region was claimed for New France and the Kingdom of France. It passed on paper to Britain in 1763 and to the United States in 1783, though Native nations held the land in practice for another half century.

The first non-Native resident was Jean Baptiste Point du Sable, a trader of African descent whose farm stood at the mouth of the river from around 1790. The US Army built Fort Dearborn there in 1803. In 1812, during the war with Britain, its garrison was attacked by Potawatomi warriors as it evacuated, and the fort was burned. After the Potawatomi were pressured to give up their remaining lands in the Treaty of Chicago of 1833, speculators rushed in. Chicago became a town that year and a city in 1837.

The Illinois and Michigan Canal opened in 1848, the same year as the first railway, and Chicago quickly became the hub of the national rail network. Grain from the prairies, timber from the northern forests and livestock for the vast Union Stock Yards, opened in 1865, all passed through it. In 1860 the Republican Party met in the city and nominated Abraham Lincoln for president.

In October 1871 the Great Chicago Fire burned for two days, killing about 300 people and leaving some 100,000 homeless. Rebuilding was rapid and ambitious. Architects working in the city developed the steel-framed skyscraper in the 1880s, and the World's Columbian Exposition of 1893 displayed the city's confidence to millions of visitors. By 1890 Chicago had passed one million people. Engineers reversed the flow of the Chicago River in 1900 to carry sewage away from the lake.

Chicago was also a centre of labour conflict, notably the Haymarket bombing of 1886 and the Pullman strike of 1894. Immigrants from Germany, Ireland, Poland, Italy and many other countries filled its neighbourhoods, and from about 1916 the Great Migration brought hundreds of thousands of Black Americans from the South, though they met segregation and a violent race riot in 1919. Prohibition in the 1920s made gangsters such as Al Capone notorious. On 2 December 1942, during the Second World War, scientists at the University of Chicago achieved the first controlled nuclear chain reaction.

After 1950 the loss of factory jobs and the movement of residents to the suburbs cut the city's population. Chicago remains the third-largest city in the United States, with about 2.7 million residents and over nine million in its metropolitan area, and it is a major centre of finance, transport and commodity trading.