Redistricting 101: Eight facts about redrawing the US political map
Redistricting occurs at least every 10 years, after new Census data determine which states have gained and lost residents. Here's a primer about the process and its consequences.
3. Who draws the district lines?
State legislatures have primary responsibility for drawing district lines in most states. To reduce the possibility of political pressure or interference, many states name bipartisan commissions to do the redistricting.
In seven states – Alaska, Delaware, Montana, North Dakota, South Dakota, Vermont, and Wyoming – the population is so small that there's only one member of the House of Representatives. Therefore, there's no need for redistricting.