| Official Name: | Stary Zagan |
| Native Name: | Старый Заган |
| Settlement Type: | Selo |
| Pushpin Map: | Russia Buryatia#Russia |
| Subdivision Type: | Country |
| Subdivision Name: | Russia |
| Subdivision Name1: | Republic of Buryatia |
| Subdivision Name3: | Mukhorshibirsky District |
| Subdivision Type4: | Municipality |
| Utc Offset1: | +8:00 |
| Coordinates: | 51.0167°N 154°W[1] |
Stary Zagan (Russian: Старый Заган) is a rural locality (a selo) in Mukhorshibirsky District, Republic of Buryatia, Russia. The population was 312 as of 2010.[2] There are 9 streets.
Stary Zagan is located 5 km southwest of Mukhorshibir (the district's administrative centre) by road. Novy Zagan is the nearest rural locality.[3]