Genetic studies of the distribution of mitochondrial DNA (mtDNA) haplogroups in human populations residing within the Carpathian Mountain range have been scarce. We present an analysis of mtDNA haplogroup composition of the Boykos, Hutsuls, and Lemkos, three population groups of the Carpathian highlands. In our study Hutsuls had the highest frequency of subhaplogroup H1 in central and eastern Europe. Lemkos shared the highest frequency of haplogroup I ever reported and the highest frequency of haplogroup M* in the region. MtDNA haplogroup frequencies in Boykos were different from most modern European populations. We interpreted these unique mtDNA frequencies to be evidence of diverse and dynamic population histories in the Carpathian highland region.