An online system receives information describing one or more interactions by each of a set of online system users with an entity having a presence in the online system, in which the information includes a geographic location of each user stored in a corresponding user profile. The online system determines multiple polygons defined at different geographic granularities, in which each polygon includes a region on a geographic map. A score is computed for each polygon based on a number of the set of users who interacted with the entity and who have a geographic location within the polygon, as well as a total number of users having a geographic location within the polygon. A polygon is selected based on the scores and a geographic location for the entity is inferred for the entity as the selected polygon at the geographic granularity of the selected polygon.