| Béal Deirg | |
| Other Name: | Belderg |
| Settlement Type: | Village |
| Pushpin Map: | Ireland |
| Pushpin Label Position: | right |
| Pushpin Map Caption: | Location in Ireland |
| Subdivision Type: | Country |
| Subdivision Name: | Ireland |
| Subdivision Type1: | Province |
| Subdivision Name1: | Connacht |
| Subdivision Type3: | County |
| Subdivision Name3: | County Mayo |
| Unit Pref: | Metric |
| Population As Of: | 2002 |
| Population Density Km2: | auto |
| Coordinates: | 54.3°N -9.55°W |
| Elevation M: | 93 |
| Blank Name: | Irish Grid Reference |
| Footnotes: | Béal Deirg is the only official name. The anglicized spellings Belderg and Belderrig have no official status. |
Béal Deirg (anglicized as Belderg or Belderrig)[1] is a Gaeltacht village and townland in County Mayo, Ireland.[2] At Belderrig Harbour there is a Mesolithic / Neolithic site dating to 4500-2500 cal. BC. The Céide Fields archaeological site lies about 6 km to the east of Belderrig.