Religious people live longer than nonreligious people, according to a staple of social science research. Yet, are those longevity benefits an inherent feature of religiosity? To find out, we coded gravestone inscriptions and imagery to assess the religiosity and longevity of 6,400 deceased people from religious and nonreligious U.S. counties. We show that in religious cultural contexts, religious people lived 2.2 years longer than did nonreligious people. In nonreligious cultural contexts, however, religiosity conferred no such longevity benefits. Evidently, a longer life is not an inherent feature of religiosity. Instead, religious people only live longer in religious cultural contexts where religiosity is valued. Our study answers a fundamental question on the nature of religiosity and showcases the scientific potential of gravestone analyses.