Gas Utilities Directory — utility profile
Ameren Illinois
Illinois · Investor-Owned · Major Regulated
Utility overview
- Utility name
- Ameren Illinois
- Legal name
- Ameren Illinois Company d/b/a Ameren Illinois
- Parent organization
- Ameren Corporation
- Ownership type
- Investor-Owned
- Utility class
- Major Regulated
- Rate jurisdiction
- Illinois Commerce Commission
- State directory
- Illinois utilities
- Customer classes
- Commercial, Residential
Official website and contact
- Official website
- www.ameren.com
- Customer service phone
- 1-800-755-5000
- Not published
Contact details are shown only where the utility publishes them.
Published state services
Illinois
Central and southern Illinois; 816,000 natural gas customers (company service-territory page).
Customer classes: Commercial, Residential
Last confirmed: August 22, 2026
State customer informationVerification sources
- Ameren Illinois Service Territory
Ameren · Official Utility Website — 816,000 NG customers; central and southern Illinois. (accessed 2026-08-22)
- Rate GDS-1 – Residential Gas Delivery Service
Ameren Illinois, Ill. C.C. No. 2 · Tariff — Legal name; residential household-purpose gas delivery. (accessed 2026-08-22)
- Rate GDS-2 – Small General Gas Delivery Service
Ameren Illinois · Tariff — Non-residential / small general delivery (commercial assignment). (accessed 2026-08-22)
- Natural Gas authority
Illinois Commerce Commission · State Regulator Inventory — ICC regulates Ameren Illinois Company (Ameren IL) as an IOU gas distributor. (accessed 2026-08-22)