Mount McKinley, also called Denali, in Alaska is the tallest mountain in the United States, at 20,320 feet (6,193 m).
On a clear day the peak can be seen from as far as 250 miles (402 km) away.
The next 16 highest peaks in the United States also are in Alaska.
Number 18 is Mount Whitney in California, at 14,494 feet (4,417 m).
The next three highest U.S. mountains are in Colorado, Mount Elbert (14,433 feet/4,400 m), Mount Massive (14,421 feet/4,395 m), and Mount Harvard (14,420 feet/4,395 m).
Hawaii’s Mauna Kea is the tallest mountain in the world, 33,480 feet (10,314 m), if measured from its base on the ocean floor to its peak.
Traditionally, though, mountains are measured based on their height above sea level.
Mount Everest is the world’s tallest mountain above sea level, at 29,035 feet (8,850 m).