DOWL Engineers was founded in Anchorage, Alaska in 1962.

DOWL Engineers began in 1962 and was founded by Lewis E. Dickenson, P.E. and Maurice P. Oswald, PLS in Anchorage, Alaska. In 1964 Alaska's Good Friday Earthquake hit Southcentral Alaska at a magnitude of 9.2. The job of rebuilding allowed the company to quickly expand, taking on two additional partners Kenneth B. Walch, P.E. and Harry R. Lee, P.E. who added the "W" and "L" to create DOWL Engineers. At the time of the merger, DOWL Engineers was a 200 person firm with offices in Alaska, Arizona and Washington. DOWL Engineers formed a partnership with NANA Development Corporation in 1996 to provide civil engineering and related services in rural Alaska. The partnership prospered and in 1999 NANA purchased a 51 percent interest in DOWL Engineers.

HKM Engineering was founded in Billings, Montana in 1955.

HKM Engineering began in 1955 by Ben F. Hurlbut as Ben Hurlbut Engineering in Billings, Montana. The firm distinguished itself as a structural consultant providing services primarily to architects and other private sector clients. In 1965, A.T. Kersich joined the firm and the name was changed to Hurlbut and Kersich Engineers. Five years later, David McCullough joined the firm to be known as Hurlbut, Kersich, McCullough. In 1977 the firm officially became HKM Engineering. Until the merger, HKM Engineering was nine offices strong across Montana and Wyoming.

Toner-Nordling & Associates was founded in Juneau, Alaska in 1945.

Toner-Nordling & Associates, Inc. was originally established by Felix J. Toner in 1945 under the name of Felix J. Toner, Registered Engineer. In 1960, Rod Nordling joined Felix Toner, and the partnership of Toner & Nordling, Registered Engineers, was formed. In 1984, the firm expanded and the name was changed to Toner-Nordling & Associates, Inc. The multi-disciplined firm provided civil engineering, land surveying, construction administration and inspection services to the Juneau area and to outlying areas in Southeast Alaska. Toner-Nordling & Associates, Inc. merged with DOWL LLC on October 1, 2007 and operated as Toner-Nordling & Associates, a Division of DOWL LLC.

Alaska Testlab was founded in Anchorage in 1954.

Alaska Testlab (ATL) has provided construction materials engineering and testing services since the establishment of the firm in 1954. ATL was the first private laboratory in Alaska to receive AASHTO accreditation. ATL also holds accreditations for soils, aggregates, Portland Cement Concrete, and bituminous concrete.