Jefferson Depot The former Gainesville Midland Railroad depot at Jefferson, built in 1906, served for a time as the town library. It is now a business office. In the second photo, the 1879 Jackson County courthouse stands in the background. Jefferson, a city of 4,000 in northeast Georgia, is the county seat of Jackson County.   Georgia's Railroad History & Heritage. Copyright, Steve Storey. Railroad History | The Depot List | Locomotives On Display | Odds & Ends | Sources & References | Home