US Time Zones: Pacific, Mountain, Central & Eastern

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  • 0:02 Origin of Zones
  • 1:35 Zone Boundaries
  • 2:12 Day Light Saving
  • 2:46 Lesson Summary
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Lesson Transcript
Instructor: Jessica Whittemore

Jessica has taught junior high history and college seminar courses. She has a master's degree in education.

This lesson will explain and show the four major time zones of the United States. It will also highlight the work of Fleming, the Standard Time Act of 1918, and daylight saving time.

Origin of Zones

Other than the fact that I can't see them on a regular basis, one of the worst parts about having family across the country is that I can never figure out when to call them. When I get up, they're still in bed and when I'm finished with work, they're still hard at it. Unfortunately, this is because we live in different time zones. Fortunately however, my little communication dilemma is an excellent segue into today's lesson on the time zones of the United States.

For starters, most countries in the world acknowledge time zones. However, this wasn't always so. In fact, time zones didn't come into play until around the year 1878, when a man named Sanford Fleming introduced them.

Due to Fleming's work, the United States was broken into four major time zones. They are Eastern, Central, Mountain, and Pacific. As you travel West through these time zones you'll find that it's almost as if you're traveling back in time, since while it is 8am in the Eastern Zone, it's 7am in the Central Zone, 6am in the Mountain Zone, and so on.

Zones Become Official

Making these time zones even more official, Congress passed the Standard Time Act of 1918. Although this made these time zones law, they were already rather accepted. In fact, even railroad companies were running their trains by them.

Despite what most of us think of when we hear the words 'zones' or 'lines', the actual boundaries of the time zones don't exist in straight lines. In fact, they don't even fall along state boundaries. Due to this, states like Texas, Kansas, Florida, Idaho, and the Dakotas find themselves broken into two zones.

Zone Boundaries

With this mention of boundaries, let's get to explaining them. Moving from east to west, we'll start with the Eastern Time Zone. Speaking generally since the zones don't fall nicely by states, the Eastern Zone includes the states on the Atlantic coast and the states that are situated on the eastern realms of the Ohio Valley. Situated sort of in the middle of the country, the Central Zone contains the states bordering the Gulf Coast, the Mississippi River, and those of the Great Plains. Aptly named, the Mountain Zone claims the area of the Rocky Mountains. Situated on our West Coast, the Pacific Zone includes the coastal states plus Nevada.

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