easternmost

Easternmost refers to the point or location that lies furthest to the east within a defined area. It is a geographic extremity used in maps, navigation, and statistical descriptions. The determination relies on longitude, which measures positions east or west of the prime meridian. In most coordinate systems, longitude values increase toward the east, making the easternmost point the one with the greatest east longitude; however, longitudes are cyclic and pass through the International Date Line at 180 degrees, which can create practical ambiguities near that line and in areas that cross it.

In practice, definitions vary by scope. The easternmost point of a country, continent, or other boundary may differ depending on whether territories are included, how coastlines are handled, and what is meant by "point" (a single coordinate vs. a continuous area). For example, the easternmost point of the contiguous United States is commonly cited as West Quoddy Head, Maine, at about 66.9 degrees west longitude. Within Europe, the eastern boundary is often placed near the Ural Mountains, making the Ural region the approximate eastern edge of Europe.

The term also appears in more specific phrases such as easternmost city, easternmost island, or easternmost settlement, each requiring its own geographic definition. Practical usage often notes the coordinate reference system and the boundary definition to avoid ambiguity, especially in regions near the International Date Line or along irregular coastlines.