Handbook of Texas Online
- Current and historical information about Harrison County.
- http://www.tsha.utexas.edu/handbook/online/articles/HH/hch8.html

Caddo Defense Organization
- Community-based wetland conservation and management group. Includes news, a calendar of events, and donation information.
- http://www.caddodefense.org/

Caddo Lake Area Chamber of Commerce and Tourism
- Includes area attractions, business directory, lodging, and restaurants.
- http://www.caddolake.org/

The Political Graveyard: Harrison County
- Lists politicians who lived or died in the county.
- http://www.politicalgraveyard.com/geo/TX/HJ.html

Sherman and Sherman Orthodontics
- Orthodontists treating children and adults using traditional and clear braces. Locations in Longview and Marshall.
- http://www.bracesbysherman.com/

Harrison County
- Site provides links and information to the county offices and services.
- http://www.co.harrison.tx.us/

Amphibians and Reptiles in Harrison County
- Texas Cooperative Wildlife Collection list of species found in the county.
- http://wfscnet.tamu.edu/tcwc/checklist/HARRS102.HTM

Harrison Central Appraisal District
- Interactive site which allows searches of property tax records.
- http://www.harrisoncad.org/