Although Iowa was the site of one of the earliest collections of tardigrades in the United States in 1873, only two additional papers on the tardigrades of this state have been published in the intervening 147 years. These earlier papers focused on tardigrades in central Iowa, living in either freshwater algae or in deciduous trees, and reported a total of only five recognized species in four genera. This project expands the known tardigrade diversity of the state through collection of specimens from both deciduous and coniferous trees in northern Iowa. Tardigrades were extracted from 29 moss and lichen samples collected from deciduous and coniferous trees in Hardin County during December 2015. 485 adult specimens and 74 eggs were collected, representing seven species (Milnesium cf. barbadosense, Milnesium burgessi, Milnesium eurystomum, Milnesium swansoni, Ramazzottius sp., Macrobiotus hibiscus, and Paramacrobiotus tonollii). Of these, one is a new species record for the United States (Milnesium cf. barbadosense), and all are new records for the state of Iowa. This is also the first report of a member of the genus Ramazzottius in Iowa. Pseudoplates, tardigrade structures that were only described for the first time in 2016, were also observed in all Milnesium specimens.