According to Wikipedia, the name was officially changed back in 1975 by the Alaskan Government. However it wasn’t recognized by the federal government until 201

According to Wikipedia, the name was officially changed back in 1975 by the Alaskan Government. However it wasn’t recognized by the federal government until 2015. Apparently the state of Ohio (which does not contain the mountain) opposed the name correction and successfully resisted for 40 years. Since Alaska was already a state in 1975 I would say that the mountain’s name was officially recognized as Denali in some states from 1975. However it took until 2015 for the rest of the country to officially adopt it.