| Country: | RUS |
| Type: | A |
| Route: | 340 |
| Length Km: | 219 |
| Established: | 2010 |
| Direction A: | North |
| Terminus A: | in Ulan-Ude |
| Direction B: | South |
| Terminus B: | Mongolian border in Khyagt |
The Russian route A340 is a Russian federal highway, connecting Russian city Ulan-Ude and Mongolia.[1]
Until 2010, the route was designated as A165. The entire route is part of AH3.