A population of 142 Mount Kenya guerezas in 22 family groups was reintroduced into Karura Forest between May 2014 and March 2016. This study evaluated changes in group size, composition, number of births and deaths, natal dispersal, and post-release settlement. Results showed increased group size and number of births, indicating successful adaptation. Settlement along riverine ecosystems informs release habitat selection and provides insights into future primate translocations.