For Reference:
Current state of congressional redistricting reform for 2021 apportionment:
Yellow = completely independent process
Green = legislature draws with substantial restrictions
Notes on restrictions:
CT and ME: 2/3rds majority of legislature required to approve a map.
FL: state constitutional amendment imposing many restrictions on partisan maps
KY: bans unnecessary county splits (has a practical impact of forcing a Dem-leaning seat in Louisville that the legislature would otherwise try to eliminate)
OH: county splitting restrictions, maps passed with support from only one party expire after 4 years instead of the normal 10
NY and UT: commission proposes maps that legislature may edit to a certain degree
NC and PA: state court rulings imposing many restrictions on partisan maps
Maximum potential for redistricting reform by voter initiative:
VA and NH do not have the voter initiative, but their legislatures have already voted to begin the process of adopting a commission. Additional action is required in both states for it to take effect.
Partisan control over the 2021 redistricting process as of today (60% shading = veto proof majority, 30% shading = control with significant external limits on map drawing):