180th meridian
![180th meridian](/Images/godic/202412/21/Earth_map_with_180th_meridian3627.jpg")
![The International Date Line zigzags around the 180th Meridian.](/Images/godic/202412/21/International_Date_Line3627.png")
![180° Meridian, Taveuni, Fiji](/Images/godic/202412/21/TodayYesterday3627.jpg")
![](/Images/godic/202412/21/Earthmap720x360_grid3627.jpg")
The 180th meridian or antimeridian is the meridian which is 180° east or west of the Prime Meridian with which it forms a great circle. It is common to both east longitude and west longitude. It is used as the basis for the International Date Line because it for the most part passes through the open waters of the Pacific Ocean. However, the meridian passes through Russia and Fiji as well as Antarctica.