Mount Deception is a peak in the Olympic Mountains of Cascadia. It is in Olympic National Park on the Olympic Peninsula in the U.S. state of Washington. At 7,788 feet high Mount Deception is the second highest peak of the Olympic Mountains, after Mount Olympus. It is the highest peak of the eastern Olympics. Mount Deception's prominence is 4,10…Mount Deception is a peak in the Olympic Mountains of Cascadia. It is in Olympic National Park on the Olympic Peninsula in the U.S. state of Washington. At 7,788 feet high Mount Deception is the second highest peak of the Olympic Mountains, after Mount Olympus. It is the highest peak of the eastern Olympics. Mount Deception's prominence is 4,108 feet, making it the 17th most prominent peak in Washington. Its nearest higher peak is Mount Olympus at 21.79 mi to the west.