Haulmark specializes in manufacturing a variety of enclosed cargo trailers. They're a division of American Cargo Group headquartered in. Trailers and haulers built to work as hard as you do, car trailers, toy haulers, motorcycle and atv trailers, cargo and utility trailers, travel trailers. Ever since it was founded in , Haulmark has been one of the most popular and reliable trailer manufacturers in the United States. The company is dedicated.