Eldorado Peak is a 8,868-foot peak, and is the 25th highest peak in Washington. The mountain is located in the North Cascades of Washington, approximately 27 miles east of Concrete. It is located in North Cascades National Park at the head of Marble Creek and just west of the Inspiration Glacier. Other glaciers in the immediate vicinity include El…Eldorado Peak is a 8,868-foot peak, and is the 25th highest peak in Washington. The mountain is located in the North Cascades of Washington, approximately 27 miles east of Concrete. It is located in North Cascades National Park at the head of Marble Creek and just west of the Inspiration Glacier. Other glaciers in the immediate vicinity include Eldorado Glacier and McAllister Glacier; thus Eldorado is flanked by the largest continuous non-volcanic ice sheet in the lower 48 states.