The 180th Meridian is often referred to as the Antimeridian. It is exactly halfway aroung the globe for the Prime Meridian, which is 0 degrees, and occurs at Greenwich, England.
The 180 meridian crosses Vanua Levu, Rambi, and Taveuni islands in Fiji.
Longitude has a minimum of -180 (west of the prime meridian) and a maximum of 180 (east of the prime meridian). -180 and 180 are the same line, approached from opposite directions. 0 degrees of longitude runs through London, England and is called the "prime meridian."
The meridian of 180° longitude (both ways, east or west)
The greatest number of degrees anyone can be from the prime meridian is 180 degrees. This is because the prime meridian itself is located at 0 degrees longitude, and the maximum longitude value is 180 degrees both east and west. Therefore, any location can be a maximum of 180 degrees away from the prime meridian.
Pacific ocean
Both of those longitudes are marked by the same meridian ... halfway around the globe from the Prime Meridian.
It doesn't matter whether you call it 180° East or 180° West, it's the same meridian either way.
-- the eastern one -- the western one
-- The "Prime Meridian" marks zero longitude. -- The "180th meridian" marks 180° longitude. The International Dateline is either on or relatively near the 180th meridian at any given latitude on it.
All places on Earth west from Prime Meridian to 180 degree are in the western hemisphere.
180 to the east and 180 to the west
The international date line