This is a historical interpretation, not a settled exclusive etymology. PDF129's age statement must not be reused as current bourbon regulatory authority.
Origins; supplied 2008 reissue of 1971 work.
Crowgey proposes a regional Old Bourbon association tied to changing county boundaries and trade. The phrase can function as a place-associated designation rather than a fixed age.
129
126
Origins
Read against supplied PDF text and images. Locators are PDF screens, not printed pages. Verified means faithful source capture, not independent historical corroboration. This is a historical interpretation, not a settled exclusive etymology. PDF129's age statement must not be reused as current bourbon regulatory authority.
No access / Whiskey Excerpts Database (USWA)
Evidence
Crowgey proposes a regional Old Bourbon association tied to changing county boundaries and trade. The phrase can function as a place-associated designation rather than a fixed age.
Location and context
No access; Origins; supplied PDF screens 126–129. These are not printed-page numbers. Edition: 2008 reissue of 1971 work.
Annotation
This is a historical interpretation, not a settled exclusive etymology. PDF129's age statement must not be reused as current bourbon regulatory authority.
Verification and use
This is a historical interpretation, not a settled exclusive etymology. PDF129's age statement must not be reused as current bourbon regulatory authority.
Faithful source capture checked against supplied text and images. This does not mean that every cited-through primary record has been independently verified.
Literature note: 
September 28 regulatory clarification
PDF129 remains a faithfully captured historical assertion, but its two-year requirement must not be generalized to bourbon. Current 27 CFR 5.143, table 1, independently checked in this review, assigns the minimum two years to straight bourbon; ordinary bourbon requires new charred oak storage without that minimum. This clarification does not independently resolve the Old Bourbon etymology.