Physiochemical differences between mitochondrial DNA (mtDNA) haplogroups that favor oxidative phosphorylation efficiency during periods of caloric limitation can lead to lifespan lengthening when food calories are less abundant. For example, prior work demonstrated that older female haplogroup H carriers had modestly lengthened lifespans beyond 60 years during the Great Depression, a time of caloric limitation in North America. The objective of the current study is to replicate the prior findings in an independent cohort that includes both sexes and younger ages. By determining and cross-referencing the mtDNA genotypes of a culturally homogeneous population isolate to the lifespans of their ancestors, we found that between 1930 and 1939, haplogroup H compared to haplogroup U carriers had a modestly lengthened lifespan (3 years) past 60 years (hazard ratio 2.35; CI95 1.41-3.90; p-value: 0.0029). The lifespan-lengthening association was apparent in both sexes but only after the age of 60. Our results provide further support for the role of mitochondrial genetics in lengthening human lifespan.