One of the primary reasons to use a map is to determine relative locations and distances of multiple points. To find the midpoint between two cities, you need a map that shows both cities and a ruler or other measuring tool.
Locate the cities on a map
Find both of the cities on the same map. Mark or put a pin in each so they are easier to find later. If the cities are too close together, find a different paper map or zoom in on an electronic map so you can see more of what lies between them.
Measure or calculate the distance
Using a ruler, measure the distance between the points that mark the cities. Look for the scale tool on the map, often located in one of the lower corners. The scale tool usually converts to inches or centimeters, sometimes both. Write the measurement of the distance between the cities in units featured on the scale tool.
Find the midpoint
Divide the distance you found by two. Measure that distance from one city, using your ruler to point in the direction of the other city. Mark the point that is half the distance between them. Convert units if necessary.