1. A method performed by data processing apparatus, the method comprising: for each of a plurality of queries stored in search log data, each of the queries comprising one or more terms, and each of the queries having one or more occurrences of the same one or more terms in the search log data: determining an origin location for each occurrence of the query, the origin location being a location from which the occurrence of the query is determined to have originated; determining a content location for each occurrence of the query, the content location being a location specified by content related to the occurrence of the query, the content location being independent of the origin location; for each of a plurality of catchment areas, determining catchment area matches for the query based on the origin location of each occurrence of the query and the content location of the occurrence of the query; determining, for each catchment area, a catchment area score that is indicative of an interest level for the catchment area for a query, the determination based on a number of catchment area matches for the catchment area for the query; and selecting, for the query and based on the catchment area scores for the catchment areas, one of the catchment areas as a selected catchment area for the query.