Black, gay woman elected Chicago mayor in historic vote

Chicago on Tuesday elected a black gay woman as its mayor and becomes the biggest city in the US to do so.

Lori Lightfoot will be the first openly gay mayor as well as the first African America woman to hold the post. 

"We were up against powerful interests," Lightfoot said in a victory speech, with her wife and young daughter by her side. 

"Today, you did more than make history, you created a movement for change," she told a cheering crowd. 

The 56-year-old formal federal prosecutor and practising lawyer won the Midwestern city's mayoral race in a one-sided victory. She was standing against Toni Preckwinkle, also a black and won by a huge margin of 74 to 26 per cent with most ballots counted.