a measurement of distance, given in degrees east or west of the prime meridian. The prime meridian is a line that runs through the Greenwich Observatory in London, England. On a map or globe, lines of longitude are drawn from the North Pole to the South Pole.
Denver, Colorado, is at 105°W (105 degrees West) longitude.
The lines of longitude on the map tell us if a city is east or west of the prime meridian.
Latitude and Longitude Finder