Alaska is both the westernmost and easternmost state in the US
Geographically, Alaska holds the title for being the northernmost and westernmost state in the United States. Surprisingly, it is also technically the easternmost state. The Aleutian Islands chain extends so far west across the Pacific Ocean that it crosses the 180th meridian line of longitude into the Eastern Hemisphere, placing Semisopochnoi Island in eastern longitudes.
The Geographic Paradox of the 50 States
Ask almost anyone to name the easternmost state in the United States, and the intuitive answer is Maine. Looking at a standard flat map of North America, Maine's jagged coast stretches farthest toward the Atlantic Ocean and Europe. It is the first place in the contiguous states to see the morning sun. Yet, under the formal definitions of global coordinate systems, the official title of the easternmost state belongs not to Maine, but to Alaska.
Alaska is universally recognized as the northernmost and westernmost state. Its territory reaches deep into the Arctic Circle and stretches across vast stretches of subarctic wilderness and open ocean. The idea that it also holds the title of the easternmost state sounds like a riddle or a cartographic error, but it is a direct consequence of how longitude, hemispheres, and coordinate grids are defined across the globe.
How Longitude and Hemispheres Divide the Globe
To understand how a single landmass can be both the westernmost and easternmost point of a nation, one has to examine the geographic grid of longitude. Longitude lines, or meridians, run from the North Pole to the South Pole. The system begins at the Prime Meridian, designated as 0 degrees longitude, which passes through Greenwich, England. Longitude values increase as you move west into the Western Hemisphere up to 180 degrees, and they also increase as you move east into the Eastern Hemisphere up to 180 degrees.
The 180th meridian sits directly opposite the Prime Meridian on the globe. It serves as the formal boundary line between the Western and Eastern Hemispheres. Anything lying between 0 degrees and 180 degrees West is geographically in the Western Hemisphere, while anything between 0 degrees and 180 degrees East is in the Eastern Hemisphere. This means that if an island chain extends far enough across the Pacific Ocean to cross the 180th meridian, its coordinates roll over from west longitudes to east longitudes.