The U.S. District Court for the District of Columbia ruled in a case brought by Texas officials, who argued the redistricting maps met the requirements of the Voting Rights Act, the Austin (Texas) American-Statesman reported.
The law requires nine states with a history of discrimination against voters, including Texas, to obtain pre-clearance from the U.S. Department of Justice before changing voting laws.
The judges in Washington found three Texas redistricting maps for U.S. House and Texas Senate and House districts did not comply with the Voting Rights Act's requirements.
The maps in question were not to have been used in the November election, so the ruling will have no impact on voting, the newspaper said.
Texas Attorney General Greg Abbott called the ruling "flawed" and promised the state will appeal.
"Today's decision extends the Voting Rights Act beyond the limits intended by Congress and beyond the boundaries imposed by the Constitution," Abbott said in a statement.