The interactive map devised by Montgomery County planners shows areas of Bethesda, Chevy Chase, Silver Spring and Takoma Park that had pervasive racial covenants for much of the 20th century.

The South Carolina NAACP challenged the redistricting in court, and a three-judge federal district court, after a nine-day hearing, ruled that new map was an unconstitutional racial gerrymander.

The challenge to the congressional map by non-Black voters tests the balancing act states must strike in complying with a civil rights law that protects the voting power of a racial minority while ...