| "Canon City" | |
| Season 12, Episode 1 | |
| [[File:|center|]] | |
| Air date | September 22, 2005 |
| Written by | Lisa Zwerling, John Wells & Joe Sachs |
| Directed by | Christopher Chulack |
| Episode Guide | |
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Canon City is the 1st episode and the twelfth season premiere of "E.R."