If you want to find patents where the earliest member of the patent's simple family is from a certain country, use the PRICN field code.

This is a funny little field, but it can be useful when you need it, and by golly we got it.

Consider this: ISD:2013 NOT PRICN:US

This says of all the granted patents in 2013, which have priorities from countries other than the US? Would you believe that more than a third (115,783) of US grants in 2013 have priorities from previously field non-US applications. It just goes to show you how truly global the patent system is!

To search for US patents that reference a particular foreign document (patent or application), use the FREFN field code.

To search for patents by a particular examiner use the PEX field code.

This field is helpful if you want to investigate the examiner who is examining your patent. Look up the patents, view the file history and get an idea of the examiner's mentality.

PEX has a companion field code ASEX for searching the Assistant Examiner field.

To search for patents where the agent is in a particular state, use the AGTS field code. Use the standard two letter codes for the state or province.

To query patents where at least one named inventor lives in a particular city, use the IC field code. If you are searching for cities and town with common names like Greenville, Franklin or Bristol, be sure to include the ICS or ICN field code as well.

This field code is interesting when doing geo searches and charting patents using the multi-series charting options.