Black fly larvae and pupae were collected from eighteen New Jersey (NJ) counties spanning all five physiographic provinces, and all five watershed management regions. Collections were made year round from small, medium, and large sized streams, and yielded a total of 40 black fly species in five genera. These collections include three new occurrence records for NJ, Simulium vittatum, S. notiale, and S. definitum; and complete NJ collection data for S. anchistinum. New county occurrence records for Prosimulium canutum, P. clandestinum, S. impar, S. parnassum and S. vandalicum are also reported. Collections included four NJ Simulium species limited to the Coastal Plain, and three species restricted to the upper Delaware River in NJ. The most pestiferous group of NJ black flies, the S. jenningsi group, was represented by seven species found in all five physiographic provinces of the state. A region along the eastern glacial terminus which includes northern NJ supports a regional simuliid species diversity that is among the highest in North America.