This chapter discusses nineteenth- and early-twentieth-century Carboniferous (Mississippian and Pennsylvanian) collections of plant fossils in the United States. There are two extensive pre-1950 collections of Carboniferous plant fossils in the United States: at the U.S. National Museum of Natural History and at Harvard University. Both of these contain many type specimens. Other less prominent historical collections, which include type or figured specimens of fossil plants, are also included in this overview on Carboniferous paleobotanical collections in the United States. The special significance of the early museum collections is that they include the research collections that contain the type specimens on which later determinations are based. In other words, the type specimens are the permanent records for taxonomic purposes. Thus, this report provides useful information for research paleobotanists who need to determine the locations of type and other specimens for taxonomic and other paleobotanical purposes.