Step 1 : Introduction to the question "What is the tallest mountain in the United States?"
Denali, once called Mount McKinley, is the tallest mountain in North America. Located in south-central Alaska, the mountain's peak is 20,310 feet above sea level. The Koyukon people who inhabit the area around the mountain have referred to the peak as "Denali" for centuries. In 1896, a gold prospector named it "Mount McKinley" in support of then-presidential candidate William McKinley; that name was the official name recognized by the Federal government of the United States from 1917 until 2015. In August 2015, the United States Department of the Interior announced the change of the official name of the mountain to Denali.