Usually on a flat map of the world the international date line is the left and right (west and east) edges of the map, but it is clearly marked on a globe.
It is known as the International Date Line.
Alaska. A small Alaskan island in the Pacific is the cutoff for the dateline. If you look on a map showing the date line, you'll see the dateline swerves in order to accommodate the US national boundary.
Map showing the location of Assam in India with state and international boudaries.
An isotherm is a line showing equal temperature.
An agonic line is a line on a chart or map showing points of zero magnetic declination.
A contour map is a physical map showing elevation and each line shows a major change in elevation.
Follow the <Related Link> below for several maps and information articles all related to the International Dateline.
Most world maps are drawn with the Prime Meridian at or near the center and the International Date Line at or near the left and/or right edge(s).
Scale Bar
Here is a link to a map http://www.sonofthesouth.net/slavery/slave-maps/mason-dixon-line.htm
The scale of contour lines on a topographic (terrain) map is called the "contour interval".
That would depend on how the map was made. Remember that the earth is a sphere, so the reference to "most eastern" is arbitrary. Even on a typical map, the reference "most eastern" could be interpreted as "What country west of the international date line is nearest to it?".