This can be done using GSAK and the Macro FilterOldestCachePerCounty.gsk . However, in order to run this macro, you would need to populate a GSAK database with every cache in the state. This would take many days to create (depending on the total number of caches in the state) as you are limited to 10 Pocket Queries a day (each with a max of 1000 caches). Project-GC provides a PQ Splitter tool to tell you what dates to put in each PQ.
https://project-gc.com/Tools/PQSplit For Ohio it currently takes 28 PQs to load a database with all the caches in the state, so that would take a minimum of 3 days to fill the database. Then you would need to decide if you are going to keep this database current with new caches and updates to handle cache changes such as archived caches. Doing database maintenance is a commitment of ongoing time and has a bit of a learning curve. Or you might just create and use the database once and if you want an updated list, you just create it again. An additional note... The county is not a field in PQs. After loading the database of all the caches in the state, you need to run the macro CountryStateCounty.gsk to populated those fields in the database. There are settings in GSAK that will automatically populate those fields when new caches are added, so that you do not need to run that County macro after any new caches are added, but that is part of the learning curve needed if you want to maintain the database for future use. Finally, keep in mind that each software uses a different set of polygons to define the county lines. There are subtle differences between what GSAK uses and Project-GC uses. So a cache that is on (or close to) a county line may end up listed in a different county when comparing the two.
