| Province: | NB |
| Type: | NB |
| Route: | 340 |
| Maint: | New Brunswick Department of Transportation |
| Length Ref: | [1] |
| Length Round: | 1 |
| Direction A: | East |
| Direction B: | West |
| Terminus A: | in Janeville |
| Cities: | Canobie, Canobie South, Rocheville, Notre-Dame-des-Erables, Haut-Paquetville |
| Terminus B: | in Hautes-Terres |
| Previous Type: | NB |
| Previous Route: | 335 |
| Next Type: | NB |
| Next Route: | 345 |
Route 340 is a 40km (30miles) long, mainly east/west secondary highway in the north-eastern portion of New Brunswick, Canada.
The route's western terminus is in the community of Janeville. The road travels south-east to the community of Canobie. Passing the community, the highway takes a 90 degree turn south passing the community of Canobie South. The highway takes a 45 degree turn and travels to the community of Rocheville before taking another turn south then another turn east going towards Notre-Dame-des-Erables, Haut-Paquetville, and eventually Hautes-Terres. There are no river crossings or intersecting routes.