| Country: | IRL |
| Type: | R |
| Image Notes: | Leckaun National School, County Leitrim, on the R278 |
| Route: | 278 |
| Length Km: | 12.6 |
| Terminus A: | R286 at Farnacardy, Sligo |
| Terminus B: | R286 at Cornalaghta, County Leitrim |
| Previous Type: | R |
| Previous Route: | 277 |
| Next Type: | R |
| Next Route: | 279 |
The R278 road is a regional road in Ireland. It is a loop road from the R286 road in Counties Sligo and Leitrim.
The R278 goes via Calry in County Sligo and passes by Doon Lough in County Leitrim. It is 12.6km (07.8miles) long.