Exhibit 21.1

SUBSIDIARIES OF AMEREN CORPORATION

AT DECEMBER 31, 2008



|                                                          |  |                                     
|--------------------------------------------------------- |  | ------------------------------------
|Name                                                      |  | State or Jurisdictionof Organization
|Ameren Corporation                                        |  | Missouri                            
|Ameren Development Company                                |  | Missouri                            
|Enporion, Inc. (21% interest)                             |  | Delaware                            
|Missouri Central Railroad Company                         |  | Delaware                            
|CIPSCO Leasing Company                                    |  | Illinois                            
|Gateway Energy Systems, L.C. (89.1% interest)             |  | Missouri                            
|Gateway Energy WGK Project, L.L.C.                        |  | Illinois                            
|Ameren Energy Resources Company, LLC                      |  | Delaware                            
|Ameren Energy Generating Company                          |  | Illinois                            
|Coffeen and Western Railroad Company                      |  | Illinois                            
|Ameren Energy Marketing Company                           |  | Illinois                            
|Illinois Materials Supply Co.                             |  | Illinois                            
|Electric Energy, Inc. (80% interest)                      |  | Illinois                            
|Midwest Electric Power Inc.                               |  | Illinois                            
|Joppa and Eastern Railroad Company                        |  | Illinois                            
|Met South, Inc.                                           |  | Illinois                            
|Massac Enterprises LLC                                    |  | Illinois                            
|AmerenEnergy Medina Valley Cogen, L.L.C.                  |  | Illinois                            
|Ameren Energy Fuels and Services Company                  |  | Illinois                            
|Ameren Illinois Transmission Company                      |  | Illinois                            
|Ameren Services Company                                   |  | Missouri                            
|Central Illinois Public Service Company, d/b/a AmerenCIPS |  | Illinois                            
|CILCORP Inc.                                              |  | Illinois                            
|Central Illinois Light Company, d/b/a AmerenCILCO         |  | Illinois                            
|AmerenEnergy Resources Generating Company                 |  | Illinois                            
|CLC Aircraft Leasing LLC                                  |  | Delaware                            
|QST Enterprises Inc.                                      |  | Illinois                            
|ESE Land Corporation                                      |  | Illinois                            
|California/Nevada Development L.L.C. (15% interest)       |  | Delaware                            
|Energy Risk Assurance Company                             |  | Vermont                             
|Missouri Energy Risk Assurance Company LLC                |  | Missouri                            
|Illinois Power Company, d/b/a AmerenIP                    |  | Illinois                            
|Illinois Power Securitization Limited Liability Company*  |  | Delaware                            
|Illinois Power Special Purpose Trust*                     |  | Delaware                            
|Union Electric Company, d/b/a AmerenUE                    |  | Missouri                            
|Fuelco LLC (33.33% interest)                              |  | Delaware                            

Subsidiaries not included on this list, considered in the aggregate as a single subsidiary, would not constitute a
significant subsidiary as of December 31, 2008.



|* |  | Dissolved February 2009
|- |  | -----------------------