The USPTO patent search site provides an unusually large set of searchable fields. For a project to advise a local city, I have searched with AC/"assignee city" and AACI/"applicant city". It also has applicant and assignee state and country. I'm looking for other patent databases, preferably free, that provide fields like this.
The field search function of WIPO's Patentscope may help. For example, the search "AAD:(San Jose)" gives any application in which the applicant's address contains the string "San Jose".
However, this only works for PCT applications. That is, while Patentscope contains some bibliographic data for applications from a whole bunch of countries, it only contains address data for PCT applications, which limits the value a bit.