||The modal age at death is a specific indicator of the "normal" duration of life: this is the age at which deaths are the most numerous. Today, deaths are concentrated at older ages in low-mortality populations. In past populations, deaths were more numerous in the first year of life and at adult ages, they were much less concentrated than today. The authors use a comprehensive database, the former Population Register of Quebec, to estimate the evolution of the modal age in the second half of the eighteenth century. They show an increase of nearly three years for men as for women, never observed also for older people, and offer an explanation based on the increase at this time of the proportion of the population living outside cities.