| Tonduff | |
| Other Name: | Tóin Dubh |
| Elevation M: | 642 |
| Elevation Ref: | [1] |
| Prominence M: | 117 |
| Listing: | Hewitt, Arderin, Simm, Vandeleur-Lynam |
| Location: | Wicklow, Republic of Ireland |
| Range: | Wicklow Mountains |
| Map: | island of Ireland |
| Map Relief: | yes |
| Translation: | Black bottom |
| Language: | Irish |
| Coordinates: | 53.1613°N -6.2673°W |
| Topo: | OSi Discovery 56 |
| Type: | Granite with microcline phenocrysts Bedrock |
| Grid Ref Ireland: | O159136 |
Tonduff [2] at 642m (2,106feet), is the 169th–highest peak in Ireland on the Arderin scale,[3] and the 202nd–highest peak on the Vandeleur-Lynam scale.[4] [5] Tonduff is in the far northeastern section of the Wicklow Mountains, in Wicklow, Ireland. The main flat summit is sometimes listed as Tonduff North, while the subsidiary summit, Tonduff East Top 593m (1,946feet), is sometimes listed as Tonduff South.[2] [6] Tonduff East Top has a prominence of only 15m (49feet), which just qualifies it as an Arderin Beg.[7] A bog on the western slopes of Tonduff, the Liffey Head Bog, forms the source of the River Liffey; bogs on the southern slopes of Tonduff, forms the source of the River Dargle.[8]