President Barack Obama will announce today that he intends to designate Browns Canyon, located in central Colorado, as a national monument.
The Denver Postreports that 21,000 acres surrounding the Arkansas River will be set aside for federal protection.
Browns Canyon, which had been classified as a Bureau of Land Management Wilderness Study Area, is a popular destination for hiking, whitewater rafting, and trout fishing.
Under the American Antiquities Act of 1906, the president has the authority to declare national monuments without authorization from Congress.
Several Colorado legislators praised the move, including current U.S. Senator Michael Bennet:
Not everyone is pleased with the unilateral move, however. In a statement, U.S. Rep. Ken Buck (R-CO) called the president "King Barack" and asked him to "cut it out."
Two other sites—Chicago's historic Pullman district and a former Japanese-American internment camp in Hawaii—will also receive national monument designation.
Read more: The Denver Post