There are 15 words that start with 'mounta'.
| mountain | mountable |
| mountains | mountainy |
| mountaineer | mountainous |
| mountaintop | mountaineers |
| mountainside | mountaintops |
| mountainously | mountainsides |
| mountaineering | mountaineerings |
| mountainousness | |
Note: These 15 words that start with 'mounta' are found from the USA & Canada version of the tournament Scrabble word list.