Mountain Time Zone is generically called Mountain Time (MT). Specifically, it is Mountain Standard Time (MST) when observing standard time, and Mountain Daylight Time (MDT) when observing daylight saving time. The term refers to how the Rocky Mountains, which range from northwestern Canada to the US state of New Mexico, are located almost entirely in the time zone. In Mexico, this time zone is known as the Zona Pacífico (Pacific Zone). In the US and Canada, the Mountain Time Zone is to the east of the Pacific Time Zone and to the west of the Central Time Zone. In some areas, starting in
Aleutian Islands Aleutian Islands The Aleutian Islands (; ; , literally "Land of the Aleuts", possibly from Chukchi "aliat", "island") are a chain of 14 large volcanic islands and 55 smaller ones belonging to both the U.S. state of Alaska and the Russian federal subject of Kamchatka Krai. They form part of the Aleutian Arc in the Northern Pacific Ocean, occupying an area of 6,821 sq mi (17,666 km) and extending about westward from the Alaska Peninsula toward the Kamchatka Peninsula in Russia, and mark a dividing line between the Bering Sea to the north and the Pacific Ocean to the south.