The United States Department of Justice approved Prince William County’s redistricting plan, which sets the names and boundaries of the county’s seven election districts for the next decade.

Prince William supervisors approved the redistricting map in April, but counties are required to submit their plan to the federal government for final approval. The DOJ reviews redistricting maps to ensure that the lines drawn don’t discriminate or dilute minority votes.

The redistricting map evenly redistributes the 400,000-plus Prince William residents. Because the county grew almost 40 percent since 2000, and much of that growth happened on the western end, county officials had to shift boundary lines so eastern districts could absorb some of the growth.

“The approval of the county’s redistricting plan is the culmination of a process that involved the entire community,” Prince William Board Chairman Corey A. Stewart (R-At Large) said. “The board ... worked diligently to make certain we had district lines that were fair and equitable to the demographics and population of Prince William County, and the Department of Justice agreed.”

Through the redistricting process, supervisors also changed the name of Republican Supervisor Maureen S. Caddigan’s district from Dumfries to Potomac.

County officials said the Urban Land Institute recommended renaming the district almost 10 years ago when it conducted a study on how to revitalize the Route 1 corridor. Urban Land Institute officials had said that naming the Dumfries district Potomac would connect the community with its natural resource, the Potomac River.

The Prince William registrar will send cards to all registered voters in the county to inform them of where to vote in the upcoming primary and election. Supervisors will, however, continue to serve the constituents in their current districts until the November election.