City-Data.com: Jefferson County, Iowa
- Profiles population demographics, jobs, housing, agriculture and crime statistics. Contains a list of recreational areas, churches, cemeteries, post offices, charts, graphs and maps.
- http://www.city-data.com/county/Jefferson_County-IA.html

Jefferson County, Iowa - US Census Bureau
- Provides population, demographic, and housing information.
- http://quickfacts.census.gov/qfd/states/19/19101.html

Iowa State University Extension - Jefferson County
- Offers agricultural, business, family and 4-H programs and resources. Includes staff directory, news, events, hours and directions. Located in Fairfield.
- http://www.extension.iastate.edu/jefferson/

Jefferson County Conservation Board
- Manages eleven areas used for outdoor activities and recreation. Includes descriptions and photographs.
- http://www.jeffersoncountyconservation.com/

Steve McLain & The Jefferson County GreenBand
- Provides repertoire list, biographies, mp3 samples, venues and photographs. Located in Fairfield.
- http://www.jeffersoncountygreenband.com/

Jefferson County, Iowa
- Features a brief overview, list of incorporated towns, links to offices and departments, history and a county map.
- http://www.jeffersoncountyiowa.com/