Global ageing, coupled with increasing urbanisation, poses the challenge to provide supportive environments where to grow old. While there is evidence of geographical variations of dementia, a systematic investigation of key environmental factors for cognitive health in older age is lacking. The study explored the association between urbanisation and cognitive functioning in older age in Ireland, and its interaction with socioeconomic status and lifestyle. The results showed that Irish urban residents had better cognitive performance than rural dwellers in relation to global cognition, verbal fluency and recall after controlling for covariates. The findings suggest an association between urbanisation and cognitive ageing which needs further exploration to identify the intervening environmental factors.