Skip to main content
U.S. flag

An official website of the United States government

This site is currently in beta, and your feedback is helping shape its ongoing development.

Return to search results

Antimeridian

Published by Pacific Islands Ocean Observing System (PacIOOS) | National Oceanic and Atmospheric Administration, Department of Commerce | Metadata Last Checked: January 27, 2026 | Last Modified: 2016-01-25T00:00:00.000+00:00
The Antimeridian is the +/-180 degree line of longitude, exactly opposite the Prime Meridian. It is often used as the basis for the International Date Line (IDL) because it passes through the open waters of the Pacific Ocean. However, this is a simplification of the actual IDL, which curtails several countries.

data.gov

An official website of the GSA's Technology Transformation Services

Looking for U.S. government information and services?
Visit USA.gov