C. H. Guernsey & Company is headquartered in Oklahoma City. The company offers a wide range of engineering, architectural and consulting solutions to clients worldwide. It serves clients in various market sectors, including commercial and industrial, defense, federal, institutions, and local and state government sectors. C. H. Guernsey & Company offers engineering services in several areas, such as public works and infrastructure, site design, transportation, construction management, building and industrial systems, and power and environmental engineering. The company also offers architectural services, including historic preservation and interior designing. Its range of consulting services include analytical, energy management and consulting, master planning, privatization and outsourcing, resource planning and security services.