- Abington
- Adams
- Addison
- Addison township
- Adkins
- Aetna
- Afton
- Albany Township
- Albany
- Alden Township
- Aledo
- Alexis
- Alexis
- Algonquin Township
- Algonquin
- Allerton
- Allin
- Alma
- Alsip
- Alto Pass Precinct
- Alto Pass
- Alton
- Amboy township
- Amboy
- Andalusia Township
- Andalusia
- Andover Township
- Anna
- Annawan township
- Annawan
- Antioch township
- Antioch
- Apple Canyon Lake
- Apple River Township
- Apple River
- Arbury Hills
- Arcola
- Arcola Township
- Arispie
- Arlington
- Arlington Heights
- Aroma
- Aroma Park
- Artesia
- Ash Grove
- Ashkum
- Ashkum Township
- Ashley
- Ashley Township
- Ashton
- Ashton Township
- Atkinson township
- Atkinson
- Atlanta
- Atlanta Township
- Atwood
- Aurora
- Aurora Township
- Aux Sable
- Ava
- Avon