| Date | Type | Code | Name |
|---|---|---|---|
| 1973-01-01 | Simple merger | 51335 → 51380 | Maclaunay → Montmirail |
| 1973-01-01 | Simple merger | 51380 | Montmirail |
| 1967-02-23 | Simple merger | 51180 → 51380 | Courbetaux → Montmirail |
| 1967-02-23 | Simple merger | 51221 → 51380 | L'Échelle → Montmirail |
| 1967-02-23 | Simple merger | 51380 | Montmirail |
| 1943-01-01 | Creation | 51380 | Montmirail |