- Abingdon
- Adams
- Addieville
- Addison township
- Addison
- Adkins
- Afton
- Albany
- Albany Township
- Alden Township
- Aledo
- Alexis
- Alexis
- Algonquin
- Algonquin Township
- Alhambra Township
- Alhambra
- Allin
- Alma
- Alorton
- Alpha
- Alsip
- Altamont
- Alto Pass Precinct
- Alto Pass
- Alton
- Altona
- Alvin
- Amboy township
- Amboy
- Andalusia
- Andalusia Township
- Andover Township
- Andover
- Anna
- Annapolis
- Annawan township
- Annawan
- Antioch township
- Antioch
- Appanoose
- Apple Canyon Lake
- Apple River Township
- Apple River
- Arbury Hills
- Arcadia
- Arcola
- Arcola Township
- Arenzville
- Argenta
- Arlington
- Arlington Heights
- Aroma
- Aroma Park
- Artesia
- Arthur
- Ash Grove
- Ash Grove
- Ashkum Township
- Ashkum
- Ashland
- Ashland Township
- Ashley
- Ashley Township
- Ashmore
- Ashmore Township
- Ashton
- Ashton Township
- Assumption
- Assumption Township
- Astoria Township
- Astoria
- Athens
- Athens North No. 2
- Athens South No. 1
- Atkinson
- Atkinson township
- Atlanta Township
- Atlanta
- Atwood
- Auburn
- Auburn
- Auburn Township
- Aurora
- Aurora Township
- Aux Sable
- Ava
- Avena
- Aviston
- Avon
- Avon