The following table ranks the 50 highest United States counties or county-equivalents by mean elevation. This list uses the "mean of extremes" elevation which is the arithmetic mean of the highest and lowest elevations. The highest U.S. county by mean elevation is Lake County, Colorado, the location of Mount Elbert and Mount Massive, the two highest summits of the Rocky Mountains of the United States and Canada. Of these 50 highest counties, 34 counties are located in Colorado, four counties in Wyoming, four counties in New Mexico, three counties in Utah, two boroughs in Alaska, and one county each in California, Idaho, and Nevada.