The biogeographic significance of Diplopoda is substantiated by 50 maps documenting indigenous occurrences of the 16 orders, the three Spirostreptida s. l. suborders – Cambalidea, Epinannolenidea, Spirostreptidea – and all higher taxa including Diplopoda itself. The class is indigenous to all continents except Antarctica and islands/archipelagos in all temperate and tropical seas and oceans except the Arctic; it ranges from Kodiak Island and the northern Alaskan Panhandle, United States (USA), southern Hudson Bay, Canada, and near or north of the Arctic Circle in Iceland, continental Scandinavia, and Siberia to southern “mainland” Argentina, the southern tips of Africa and Tasmania, and Campbell Island, subantarctic New Zealand. The vast, global distribution is interrupted by sizeable, poorly- or unsampled areas including the Great Basin, USA; the Atacama Desert region of Chile and neighboring countries; southern South American islands; the central Kalahari and Sahara deserts; the Gobi Desert, Mongolia, and all of north-central and western China; from north of the Caspian Sea, Russia, to central Kazakhstan; and the “Outback” of central Australia. Five Arabian countries lack both samples and published records of indigenous diplopods – Bahrain, Kuwait, Oman, Qatar, and United Arab Emirates – as do Turks and Caicos, in the New World, and Mauritania and possibly Egypt, Africa. New records, including the first for Chilognatha from Botswana and the first specific localities from Northern Territory, Australia, are cited in the Appendix. Increased emphasis on mappings in taxonomic research is warranted along with investigations of insular “species swarms” that constitute a microcosm of the early evolution of the class. The largest “species swarm” in the Diplopoda is Diplopoda itself!