CDG Engineers was established in 1992 as part of a reorganization of a firm that was originally founded in 1941 as Neal J. Campbell Consulting Engineers. Today, CDG Engineers has over 100 personnel located in three offices. CDG’s headquarters is located in the southwestern part of the City of St. Louis (in the Hill) in a building known as Campbell Plaza. The building is owned by several stockholders of CDG, and this ownership enables the company to expand as the need for additional staff develops.

CDG also has a branch office located in Sheridan, Wyoming to serve the needs of our mining clients located in the Powder River Basin, as well as an office in Troy, Illinois to offer services to additional clients in the Metro St. Louis area. CDG most recently opened an office in Charlotte, North Carolina in 2021 to support clients in the Eastern region of the U.S.