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Host-specific parasites exhibit close co-evolutionary associations with their hosts. In the case of fragmented/disjunct host distribution, host-specific parasites may reflect the biogeographical history of regions and/or the role played by contacts of hosts. The present study was focused on <i>Dactylogyrus</i> (Monogenea) species almost exclusively parasitizing cyprinoid fishes. We investigated the phylogenetic relationships between <i>Dactylogyrus</i> parasites of Nearctic cyprinoids (Leuciscidae) and <i>Dactylogyrus</i> parasites of Palearctic cyprinoids and used <i>Dactylogyrus</i> phylogeny to explore the biogeography of fish hosts in Europe and North America. Phylogenetic analyses revealed that two Nearctic clades of <i>Dactylogyrus</i> spp. have different origins. Historical contacts between European and North American leuciscids were accompanied by the host switching of <i>Dactylogyrus</i> species. In the Nearctic region, <i>Dactylogyrus</i> parasites also colonized non-leuciscid fishes. <i>Dactylogyrus</i> spp. of three Nearctic leuciscid clades were included in the phylogenetic reconstruction; only <i>Dactylogyrus</i> spp. of the Plagopterinae had a common origin. <i>Dactylogyrus</i> species did not reflect the phylogenetic relationships among leuciscid clades, suggesting that past co-diversification was overshadowed by colonization events mediated by paleogeographic and climatological changes and extensive drainage reorganization. Host-specific monogeneans serve as a supplementary tool to reveal the historical biogeographical contacts between freshwater fish from the North America and Europe and also contemporary contacts of leuciscids in North America.