Three years after the last census noted changes in population and demographics in the United States, several states are still wrangling over the shape of congressional or state legislative districts. Redrawn maps are being challenged on grounds they are racially discriminatory, overly partisan or both.

Redistricting litigation is ongoing in several states, including Florida, Georgia and Louisiana, where Democrats are hoping to make gains. Most recently, New York’s highest court gave Democrats a chance to redraw the state’s congressional districts, a major victory as the party tries to win control of the U.S. House next year.

Democrats also are expected to gain a seat in Alabama, where districts were revised after federal judges ruled that the original map enacted by Republican state officials had illegally diluted the voting power of Black residents.

“The parties are fighting these battles district by district in courtrooms across the country that are aimed at giving Democrats a better chance at the starting gate,” said New York Law School professor Jeffrey Wice, who focuses on redistricting. “Each court victory counts in a major way.”

Here’s a look at the status of redistricting challenges for congressional and state legislative boundaries across the U.S:

Contributing: Anthony Izaguirre, Associated Press