Hamilton County Tennessee Genealogy Resources, Chattanooga

It doesn't look like I have any ancestors from Hamilton County, Tennessee. However, since I live close to this fairly old and important community, I want to learn more about it so I can help other people with their research.

Hamilton County Library Genealogy Resources
I called to see if they had resources onsite, and was told that they don't currently have a genealogy department apart from an extensive collection on the website.
https://chattlibrary.org/resources-genealogy/

Hamilton County Tennessee Genealogical Society
A very professional looking website which states, "HCTGS is an Internet based society ... to share their knowledge of Hamilton County with others on the Internet and provide a forum for fellow researchers interested in the genealogy and history of Hamilton County Tennessee."
http://www.hctgs.org/

East Tennessee Historical Society
Offers programs and exhibitions uniquely tailored to the region. A great list of Affiliates, Local Societies & County Historians, which names four different organizations in Hamilton County and resources for adjacent counties.
http://easttnhistory.org/

Family Search Wiki: Hamilton County Tennessee
Helpful information about researching in Hamilton County, the 1910 Hamilton County Courthouse fire which destroyed many records, including all of the antebellum records.
https://www.familysearch.org/wiki/en/Hamilton_County,_Tennessee_Genealogy

Hamilton County History and Genealogy
Volunteers dedicated to making local history and genealogy records available for free online, including Churches, Obituaries, Military,  and Native Americans.
http://genealogytrails.com/tenn/hamilton/

Facebook group: Chattanooga Delta Genealogy Society
This group doesn't appear to be very active. 
https://www.facebook.com/ChattDeltaGenSoc/