Redistricting commission

In the United States, a redistricting commission is a body, other than the usual state legislative bodies, established to draw electoral district boundaries. Generally the intent is to avoid gerrymandering, or at least the appearance of gerrymandering, by specifying a nonpartisan or bipartisan body to comprise the commission drawing district boundaries.
Nonpartisan or bipartisan commissions as of 2010.
Currently, 21 U.S. states have some form of non-partisan or bipartisan redistricting commission. Of these 21 states, 13 use redistricting commissions to exclusively draw electoral district boundaries (see below). A 14th state, Iowa, uses a special redistricting process that uses neither the state legislature nor an independent redistricting commission to draw electoral district boundaries (see below).
In 2015, the U.S. Supreme Court ruled in "Arizona State Legislature v. Arizona Independent Redistricting Commission" that redistricting commissions such as Arizona's, whose redistricting commission process is independent of the state legislature, were constitutional.
For purposes of these tables:
Iowa is a special case:
Additionally, Maine and Vermont use advisory committees for redistricting. Connecticut, Illinois, Mississippi, Oklahoma, and Texas have backup redistricting commissions, if efforts at redistricting via the usual legislative process fail.
2021 redistricting.
In 2021, following the 2020 census, multiple states will begin using new, non-partisan commissions or systems to redraw their legislative and/or congressional districts