Reilly’s Law of Retail Gravitation

William J. Reilly’s law of retail gravitation asserts that groups of customers are drawn to certain retail locations because of factors like the distance to the market, the distance between markets, the market population, the size of the retail establishment, the location of competitors, etc.

For example, it assumes that the greater the distance, the less likely buyers are to travel, but that they are willing to travel longer distances to larger retail centers.