The U.S. National Geographic Society says Crimea will be shaded in gray as an "Area of Special Status" on its maps once the territory has been formally annexed by Russia, Radio Free Europe/Radio Liberty reports.
Simferopol, its administrative center, would be designated by a special symbol.
The American mapmaker said the decision was in line with its policy on contested territories.
It said its actions do not suggest recognition of the legitimacy of the situation.
Earlier, U.S. media quoted National Geographic officials as saying it would show Crimea as part of Russia once the Russian parliament ratifies legislation on the move.