The LH7 Ranch, in western Harris County, was established by Emil Henry Marks in 1907. Marks's grandparents were Prussian immigrants; his father, A. T. Marks, was born as their ship arrived at Galveston in 1843. E. H. Marks was born on October 26, 1881, at Addicks, the youngest of A. T. and Elizabeth (Schulz) Marks's two daughters and three sons. Orphaned at age ten, E. H. began working as a cowboy for an uncle who ranched at Pattison on the Brazos River. He later worked for other East and Southeast Texas ranchers. In 1898 he registered the LH7 brand in Harris County. The letters had no special significance; the seven represented the number in his family. In 1907 Marks married Maud May Smith of Fairbanks and started ranching on sixty-three acres east of Addicks. In December 1917 he moved the LH7 Ranch three miles west to 640 acres of prairie near Barker. To entertain neighboring ranchers who helped him with the spring branding of 1918, at a time of manpower shortages during World War I, Marks staged a small riding and roping contest. The branding party grew into an annual ranch rodeo that attracted large crowds from nearby Houston for thirty years.
Marks was among the first Gulf Coast cattlemen to cross Brahman bulls imported from India with the common longhorn cattle. By 1924 he was using three Brahman bulls on the LH7, one from the estate herd of Abel H. (Shanghai) Pierce and two imported from Brazil. Highly resistant to heat and parasites, the breed proved exceptionally well-suited to the rigors of the Gulf Coast climate. The LH7 became an important supplier of quality Brahman breeding stock for ranges from South Texas to Florida. At the same time, Marks protected the foundation stock of the LH7-the Texas longhorn-from extinction. As early as 1923 he began hand-picking a herd of the old-time Texas cattle to keep the breed alive. Choosing outstanding specimens from the thousands of East Texas cattle he traded in, Marks built one of the nation's finest and largest herds of authentic longhorns. By the 1930s, when the LH7 was running 6,670 head of crossbred range cattle on a 36,000-acre lease west of Houston (between Highway 90 and Hockley), Marks was separately maintaining a herd of 500 pure Texas longhorns. With the revival of the breed, the Marks line became one of the "seven families" of longhorn cattle, as determined by the Texas Longhorn Breeders Association of America (established in 1964).
Ranch operations were severely curtailed during the Great Depression. In January 1936 Marks and Houston oilman W. A. Paddock dissolved a thirteen-year partnership in the ranch, and Marks was left with little more than his private longhorn herd and about 1,000 acres. It was the end of the LH7 as one of the largest ranches in Southeast Texas. World War II took a further toll; to protect the war industries at Houston from flooding along Buffalo Bayou, the United States Army Corps of Engineers claimed 450 acres of the LH7 for the Addicks-Barker flood-control reservoirs, built in 1945–48. The condemned land included the LH7 rodeo grounds, and Marks abandoned the annual ranch rodeo.
In January 1952 he rode with three others in the first Salt Grass Trail Ride, thus inaugurating one of Houston's most enduring traditions. The trail ride is reenacted each February to kick off the Houston Livestock Show and Rodeo. Though well into his eighties, Marks continued to ride horses and work cattle. He died in Houston on September 15, 1969. The LH7 Ranch at Barker passed to his youngest daughter, Maudeen Marks, who continued to maintain a herd of longhorns on land surrounded by Houston. After their father's death, Maudeen and her brother Travis agreed to share the LH7 brand for their separate longhorn herds at the original LH7 Barker headquarters, at Maudeen's newer ranch near Bandera, and at Travis's ranch near Fannin. In 1985 the Texas Historical Commission designated the LH7 a state archeological landmark.