From the website:
Districting for ArcGIS is an add-on that allows you to create defined groupings of geographic data, such as census tracts, ZIP Codes, and precincts, by creating a districting plan.
With Districting for ArcGIS, you can
* Redraw political boundaries.
* Set up territories to streamline sales efforts.
* Define districts for voting, schools, and fire services.
* Analyze statistics and data concerning population densities, housing breakdowns, income, and race.