Eastern Standard Time • Central Standard Time Mountain Standard Time • Pacific Standard Time Wiki Quote: Zones used in the contiguous U.S. From east to west, these zones are: 1. * Eastern standard time zone: (EST; UTC-5; Zone R), which comprises roughly the states on the Atlantic coast and the eastern two thirds of the Ohio Valley. 2. * Central standard time zone: (CST; UTC-6; Zone S), which comprises roughly the Gulf Coast, Tennessee Valley, and Great Plains. 3. * Mountain standard time zone: (MST; UTC-7; Zone T), which comprises roughly the states that include the Rocky Mountains. 4. * Pacific standard time zone: (PST; UTC-8; Zone U), which comprises roughly the states on the Pacific coast, plus Nevada.