Cox is the latest big media company to put up big bucks for naming rights to part of the new Newseum.
Cox will pay $6 million to sponsor the First Amendment gallery at the museum, which just announced it will re-open Oct. 15 in its new digs near the Capitol after a five-year hiatus.
The gallery will deal with the First Amendment's five freedoms: religion, speech, press, assembly and petition.
Cox becomes the ninth name partner in the museum, which is backed by the Freedom Forum, successor to the Gannett Foundation.
Those nine have kicked in $59 million toward the total $435 million project which combines a museum with retail and residential space. The others are News Corp.; NBC Universal; Time Warner; Hearst Corporation; ABC News/Walt Disney Company; and the Ochs-Sulzberger, Pulliam, and Greenspun newspaper families.