With more than 93 years of growth, HNTB Corporation has become one of the most prominent engineering, architecture and planning firms in the United States. The employee-owned company, with more than 3,400 employees and 62 offices nationwide, serves clients in the transportation, architecture and federal markets with technical excellence and a commitment to performance providing work, on time, on budget and to the client's satisfaction. HNTB is a multidisciplinary firm known for its work in transportation, bridges, aviation, architecture, urban design and planning, environmental engineering, water and construction services. Founded in 1914, HNTB has designed movable bridges, the first modern turnpike and a significant portion of the U.S. interstate system. HNTB has a location in St. Louis, Mo.