International Date Line

The International Date Line

The International Date Line is an imaginary line in the water. It runs between the South and North Poles. This line helps us know when one day ends and the next begins. It goes mostly through the Pacific Ocean and follows the 180.0° line of longitude. Sometimes it bends around islands to help nearby places.

When you travel west and cross this line, you gain a day. If you go east and cross it, you lose a day. It is not a real wall or fence. It is just a way for mapmakers to keep time organized around the world.

The line sometimes moves because countries ask for it to change. This helps them plan better and match their time with neighbors.

Traveling Around the World

When people travel around the world, they change their clocks. If you go west, you move your clock back one hour for every 15 degrees you travel. But when you cross the International Date Line going west, you move your clock forward by a whole day. If you travel east, you move your clock forward one hour for every 15 degrees. But when you cross the line going east, you move your clock back a whole day.

Fun Places Near the Line

The line passes near many interesting places. It moves east of Wrangel Island and the Chukchi Peninsula in Russia. It goes through the Bering Strait between the Diomede Islands. It bends west of islands like St. Lawrence Island.

It crosses between the U.S. Aleutian Islands and Russia’s Commander Islands. It bends around Guam and the Northern Mariana Islands. Near the equator, it swings east around Kiribati, an island country.

Two tiny U.S. islands, Howland Island and Baker Island, are among the first places to start a new day. The line then passes between Samoa and American Samoa. It goes near Tonga and ends near Antarctica, where it isn’t usually shown on maps.