U.S. District Judge Sim Lake said the Bible must be removed within 10 days and Harris County must pay $41,000 in court costs and attorney fees, the Houston Chronicle reported.
Kay Staley, a real estate broker and attorney, filed a lawsuit against the county contending the display violates the First Amendment ban on establishment of religion.
The 4-foot stone monument, which contains The King James Bible under glass, was constructed with private funds during the 1950s as a memorial to a Houston philanthropist.
Harris County argued the display primarily honored William Mosher, but the plaintiffs said it unconstitutionally promotes a specific religion at a government building.
County Judge Robert Eckels said he was disappointed in the federal court's decision and would appeal.