This paper is a survey of the Oribatid mites of the North American deserts. It contains four chapters. Chapter 1 gives an overview of the biology of mites and oribatids. I talk about their phylogeny, body parts, food sources, habitats, and lifecycle. In Chapter 2, I identify a group of 59 oribatid species with cosmopolitan or semi-cosmopolitan distributions and examine how the number of biogeographical regions where a species has been detected relates to body length and to reproductive mode (sexual or parthenogenetic). I also present an illustrated guide (File S1) to 58 of these species for use in identifying cosmopolitan species in oribatid surveys. Chapter 3 describes the current state of knowledge of oribatid diversity in the southwestern US and northern Mexico. In total, I was able to find records for 340 oribatid species from this region in the published literature and museum collections. However, we can see that some states, such as Arizona and Sonora, do not have many published records and that further studies are needed to more fully characterize oribatid diversity within this region. Finally, Chapter 4 describes some preliminary efforts to culture oribatid mites sampled from oak woodland in the Santa Rita Mountains of southeast Arizona. Although this work was interrupted by the COVID-19 crisis, I was able to keep three oribatid species in captivity long enough for them to lay eggs and for some of these eggs to hatch.