The mileage marker for any object is its position on a defined route, such as a highway or a road, which is measured in miles. It is often expressed with a few decimal places for greater precision.

The number locates the object by distance along the defined route. A decimal value can express a position between whole-mile points.

The value describes route position and need not identify a physical roadside marker. A kilometer marker describes the corresponding kind of route position using kilometers.