user: Question: what is the most recent date founded in Elk County?
Columns: ['Park name', 'County or counties', 'Area in acres (ha)', 'Date founded', 'Stream(s) and / or lake(s)']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Allegheny Islands State Park', 'Allegheny County', '43acres (17ha)', 1980.0, 'Allegheny River']
SQL:

assistant: SELECT MAX("Date founded") FROM "Table" WHERE "County or counties" = 'Elk County';