Per Wikipedia (yeah, I know...):
The Federal government officially adopted the name Mount McKinley in 1917 when Congress passed and President Woodrow Wilson signed into law "An Act to establish the Mount McKinley National Park in the territory of Alaska", which singled out the area in the Mount McKinley region...
The name for the mountain was reestablished in1980 when they named the reserve Denali, but kept the mountain name as McKinley as a compromise. So much for compromise.