In microeconomics, a threshold population is the minimum number of people needed for a service to be worthwhile. In geography, a threshold population is the minimum number of people necessary before a particular good or service can be provided in an area. The concept is equivalent to the "range" in central place theory and retailing, which delineates the market area of a central place for a particular good or service, and is dependent on the spatial distribution of population and the willingness of consumers to travel a given distance to purchase particular goods or services.