The Mifflin Street Block Party, commonly called "Mifflin," is an annual event held on the last Saturday of April in Madison, Wisconsin, primarily attended by students from the University of Wisconsin–Madison. The party began in 1969 as a protest and has since become a large social event with music and alcohol, occurring annually on Mifflin Street. For example, in 2024, it was held on April 28, and the 2025 event was scheduled for Saturday, April 26.