From June 20th - July 6th, 2019, an international team of 35 entomologists from 15 countries attended Fly School II: A Course for Dipterists in Los Osos, California, sponsored by the Los Angeles County Natural History Museum. We extensively sampled for Diptera at 17 main sites, with Camp Keep (GPS N 35.29, W -120.88) as the camping quarters, representing a broad range of habitats within San Luis Obispo County. A variety of collecting methods were employed, including both active (e.g. sweep sampling, hand netting, and aspirating) and passive (e.g. Malaise, Shannon, and light traps) techniques. Flies were identified to lowest taxonomic level possible based on expertise using the most relevant literature available, and specimens are permanently housed at a variety of locations around the world. A full checklist of taxa based on these data will be included in a forthcoming publication in the Pan-Pacific Entomologist. Co-contact: Brittany Wingert - bwingert@ualberta.ca Co-contact: Andrea Kautz - akautz14@gmail.com Co-contact: Brian Brown - bbrown@nhm.org