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, for each of a plurality of catchment areas, catchment area matches for the query based on an origin location of each occurrence of a query and a content location of each occurrence of the query, wherein a first catchment area is a subset area of a second catchment area, and the second catchment area is a subset of a third catchment area; determining, for each of a plurality of catchment areas, wherein the each catchment area belongs one of a plurality of catchment area types, 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; determining a respective catchment area score threshold for the first catchment area type, second catchment area type, and the third catchment area type; selecting a catchment area for a query, the selecting comprising: selecting the first catchment area type if the catchment area score for the first catchment area type meets its respective threshold and the catchment area scores for the second catchment area type and the third catchment area type do not meet their respective thresholds; selecting the second catchment area type if the catchment area score for the second catchment area type meets its respective threshold and the catchment area score for the third catchment area type does not meet its respective threshold; or selecting the third catchment area type if the catchment area score for the third catchment area type meets its respective threshold.