The Chicago mayoral election of 1891 saw "Reform" candidate Hempstead Washburne narrowly win a four-way race against incumbent Democrat DeWitt Clinton Cregier, former mayor Carter Harrison Sr., and Citizens Party nominee Elmer Washburn. Also running was Socialist Labor candidate Thomas J. Morgan. Due to the four-way split in popular support, Washburne won with merely a 28.83% vote share; less than a quarter-of-a-percent margin of victory over second-place finisher Cregier and only 2.47% ahead of third-place finisher Harrison.
Before running in the general election as an independent Democrat, former mayor Harrison challenged Mayor Cregier for the Democratic Party's nomination. A primary was held to select the delegates to the city's Democratic Party convention. Cregier prevailed in getting more delegates supporting his renomination elected than delegates supporting Harrison for mayor. As a result, Cregier won the party's nomination at the convention.