In general, Tucson and Pima County support the Democratic Party, as opposed the state's largest metropolitan area, Phoenix, which usually supports the Republican Party. Congressional redistricting in 2013, following the publication of the 2010 Census, divided the Tucson area into three Federal Congressional districts (the first, second and third of Arizona). The city center is in the 3rd District, represented by Raul Grijalva, a Democrat, since 2003, while the more affluent residential areas to the south and east are in the 2nd District, represented by Republican Martha McSally since 2015, and the exurbs north and west between Tucson and Phoenix in the 3rd District are represented by Democrat Ann Kirkpatrick since 2008. The United States Postal Service operates post offices in Tucson. The Tucson Main Post Office is located at 1501 South Cherrybell Stravenue.

Which political party does Tucson usually support?