A milestone is a numbered marker placed on a route such as a road, railway line, canal or boundary. They can indicate the distance to towns, cities, and other places or landmarks like mileage signs; or they can give their position on the route relative to some datum location. On roads they are typically located at the side or in a median or central reservation. They are alternatively known as mile markers, mileposts or mile posts. A "kilometric point" is a term used in metricated areas, where distances are commonly measured in kilometres instead of miles. "Distance marker" is a generic unit-agnostic term.