There are 9 words that start with 'decong'.
| decongest | decongests | 
| decongested | decongestant | 
| decongesting | decongestion | 
| decongestive | decongestants | 
| decongestions | |
Note: These 9 words that start with 'decong' are found from the USA & Canada version of the tournament Scrabble word list.