CHG Healthcare Services was founded in 1979 by Therus C. Kolff, MD, to deliver medical care to rural areas of the western United States. The company is based in Holladay, Utah, though the postal designation of nearby Salt Lake City is used in its mailing address. CHG Healthcare was originally known as CompHealth, and now includes a collection of healthcare related companies such as: CompHealth, Weatherby Healthcare, RNnetwork, Foundation Medical Staffing, and Global Medical Staffing which was purchased in 2016. The CHG family of companies is one of the largest providers of healthcare staffing in the United States, with 31% market share in locum tenens revenue. Their services also include both temporary and permanent placement of physicians, nurses and allied health professionals. CHG employs over 1,800 people in seven offices located around the United States, doing business in all 50 states.