The family Dolichopodidae is reviewed in an area including the entire Southeastern United States. Keys and records of distribution are provided for 44 genera and 599 species with notes on additional species. Four genera, Harmstonia, Nanomyina, Neurigonella, Sympycnidelphus, and the following 55 species are described as new: Argyra grayi, Asyndetus hardyi, Chrysotus caroliniensis, C. furcatus, C. lamellifer, C. litoralis, C. tennesseensis, Condylostylus brimleyi, Diaphorus canus, D. intermedius, D. iowensis, D. laffooni, D. pseudopacus, Dolichopus albivestitarsis, D. steyskali, Enlinia ciliata, E. saxicola, Gymnopternus aldrichi, G. annulipes, G. anomalocerus, G. campsicnemoides, G. constrictus, G. cumberlandensis, G. cuneicornis, G. flaviventris, G. floridensis, G. hybridus, G. laffooni, G. meniscoides, G. nigricomus, G. ohioensis, G. propriofacies, G. puseudodebilis, G. sharpi, G. tennesseensis, G. vockerothi, G. weemsi, Harmstonia intricata, H. pectinicauda, Micromorphus bifrons, M. longilamellatus, Nanomyina litorea, Neurigona nigritibialis, Paraclius aberrans, P. floridensis, Pelastoneurus angulatus, P. brevis, Rhaphium vockerothi, Sciapus unicoiensis, Sympycnidelphus sharpi, Thinophilus flavicaudatus, T. semipallidus, T. vespertinus, Thrypticus dissectus, T. setosus. Diaphorus pseudopacus crinipes is described as a new subspecies. Two new names were erected: Diaphorus vanduzeei for D. communis Van Duzee nec D. communis White, Peloropeodes discolor for P. frater Robinson nec P. frater (Aldrich). The following new synonymy was established: Campsicnemus wheeleri Van Duzee (= Thinophilus variabilis Van Duzee), Chrysotus discolor Loew (= cobaltinus Van Duzee), C. palpiger (Wheeler) (= spinifer Malloch), C. parvicornis Van Duzee (= exiguus Van Duzee), C. subcostatus Loew (= pratincola Wheeler), Condylostylus crinitus (Aldrich) (= albiapicatus Parent), Diaphorus leucostoma Loew (= vittatus Van Duzee), Dolichopus gratus Loew (= mercieri Parent), Gymnopternus lunifer Loew (= exiguus Loew), G. spectabilis Loew (= chalcochrus Loew), Hercostomus chetifer (Walker) (= dreisbachi Harmston & Knowlton, ornatus (Van Duzee)), H. setosus (Van Duzee) (= torridus Harmston & Knowlton), H. unicolor Loew (= ornaticauda Van Duzee), Lamprochromus canadensis (Van Duzee) (= Telmaturgus brevicornis Robinson), Medetera aberrans Wheeler (= lobata Van Duzee), M. caerulescens Malloch (= distincta Van Duzee), Paraclius claviculatus Loew (= fraternus Van Duzee), P. alternans (Loew) (= vicinus Aldrich) Pelastoneurus aurifacies Van Duzee (= minutus Van Duzee), P. laetus Loew (= falcatus Aldrich, ramosus Van Duzee), P. lamellatus Loew (= cristatus Van Duzee), P. longicauda Loew (= quadricincta Van Duzee), P. nigricornis Van Duzee (= penicillatus Parent), P. proximus Aldrich (= arboreus Van Duzee), P. vagans Loew (= longilamellatus Parent), Peloropeodes salax Wheeler (= flavipes Van Duzee), Rhaphium foliatum Curran (= fuscicosta Van Duzee), R. lugubre Loew (= impetuum Curran), R. melampus (Loew) (= Systenus americanus Van Duzee), R. rotundiceps (Loew) (= fumipenne (Loew)), Sciapus dorsalis (Loew) (= Condylostylus viridivittatus H. Robinson), S. scintillans (Loew) (= dubiosus Van Duzee, fulgidus Parent), Thinophilus viridifacies Van Duzee (= nigripilosus Van Duzee, Chrysotus quadratus Van Duzee). The following transfers have been made: Achalcus sordidus Aldrich to Enlinia, Chrysotus parvus Van Duzee to Telmaturgus, Diaphorus cylindricus Van Duzee to Nematoproctus, D. palpiger Wheeler to Chrysotus, D. rauterbergi Wheeler to Chrysotus, Neurigona dorsalis Van Duzee, setosa Van Duzee, and tibialis Van Duzee to Hercostomus, N. minima Van Duzee to Micromorphus, N. minuta Van Duzee to Systenus, N. nigricornis Van Duzee and sombrea Harmston & Knowlton to Neurigonella, Paraclius albonotatus Loew, angulatus Van Duzee, indianus Harmston & Knowlton, mysticus Becker to Tachytrechus, Polymedon notatus Van Duzee to Tachytrechus, Sympycnus canadensis Van Duzee to Lamprochromus, Telmaturgus satrapa (Wheeler) to Lamprochromus.