The term Ultra is applied to any mountain whose topographic prominence equals or exceeds 1,500 metres (4,921 feet). Prominence measures how much a summit rises above its surroundings rather than its absolute elevation above sea level. Peaks meeting this threshold are often called "Ultras" or "P1500" and are valued both by geographers and by climbers seeking independent, dominant summits.

What topographic prominence means

Prominence is calculated as the vertical distance between a summit and the lowest contour line encircling it and no higher summit. This lowest point is known as the key col. A high-prominence mountain stands clearly above nearby terrain and is usually visually and geographically distinct from neighboring peaks. Prominence emphasizes a mountain's individuality rather than just its height.

Distribution and the U.S. list

There are 128 mountains in the United States that qualify as Ultras. They are not evenly spread: Alaska contains the largest concentration, including many rugged ranges and long-distance cols, while the western contiguous states (Cascades, Sierra Nevada, Rockies) and the Hawaiian Islands also contribute several entries. Lists of these peaks are compiled and updated by mapping authorities, researchers, and peakbagging communities.

Notable examples and distinctions

  • Denali (Alaska) — a globally prominent summit and the highest peak in North America.
  • Mauna Kea and Mauna Loa (Hawaii) — prominent both above sea level and when measured relative to surrounding ocean basins.
  • Mount Rainier (Washington) — a major visual landmark with large local relief.

Prominence differs from elevation (absolute height above sea level) and from topographic isolation (distance to the nearest higher terrain). A mountain can be very high but have low prominence if it is a subsidiary summit of a higher neighbor.

Uses, measurement, and resources

Ultras are useful for scientific classification, conservation priorities, and mountaineering goals. Advances in digital elevation models, topographic mapping, and GPS surveying have refined prominence estimates and occasionally alter which summits qualify. For sortable catalogs, maps, and detailed tables of the 128 U.S. Ultras — including elevation, prominence, and coordinates — see curated peak lists and databases maintained by researchers and peakbagging organizations (Ultra listings and data portals).