westernmost

Westernmost is a geographical descriptor used to indicate the location that lies farthest to the west within a defined set of places or features. It is a relative term that depends on the boundaries of the area being considered, such as a country, region, continent, or dataset.

Definition and method

Westernmost locations are determined by longitude relative to the prime meridian at Greenwich. In the common system, longitudes west of Greenwich are treated as negative values, so the westernmost point is the one with the smallest longitude (or, in a 0–360 system, the largest western longitude). Because the 180th meridian marks the boundary between the western and eastern hemispheres, positions near that line can be described as either westernmost or easternmost depending on the convention used.

Uses and scope

The term is used in political geography (westernmost point of a country), regional geography (westernmost town or coastline), and physical geography (western extremity of a landform). It can also appear in travel writing, cartography, and legal descriptions of borders.

Examples

The westernmost point of mainland Europe is Cabo da Roca in Portugal. The westernmost point of the contiguous United States is Cape Mendocino, California. If all U.S. territories are included, the westernmost point lies on Attu Island in Alaska, near the 180th meridian, illustrating how near-meridian cases can complicate a simple label.

Notes

Because longitude and hemispheric conventions vary, the designation of “westernmost” may differ across sources. The term remains a straightforward way to express extremity in the west within a specified framework.