Every two years in the United States, districts in each state elect representatives to the U.S. House of Representatives. The district boundaries are not permanent; rather, they are redrawn every ten years in a process known as redistricting. Mathematics is useful in understanding this important and often contentious process. Redistricting is a rich context for teaching and learning mathematics, one that illuminates both American democracy and important mathematical ideas. This article offers suggestions for classroom implementation as well as resources for further exploration. (Contains 4 figures, 1 table and 8 online resources.)