The Plymouth Oil Company was organized in Pittsburgh, Pennsylvania, on October 19, 1923, under the laws of Delaware as a holding company for the Big Lake Oil Company, located on University of Texas land in Reagan County. Renowned wildcatter Michael L. Benedum founded the company to develop the Big Lake oilfield, in which the Plymouth owned a three-quarter interest, and to engage in all facets of the Texas petroleum industry. Officers were: president, Walter Hallanan, Sr., vice president, Jerome Farquaher, and secretary and treasurer, W. E. Huston. The POC's Big Lake company, a separate entity, implemented a drilling program and began Texon, a camp with employee housing. In 1924 well No. 9 assured the field's success, opened the Permian Basin for oil exploration and growth, and greatly enriched the University of Texas. By 1929 the POC had two producers in Pecos County. In 1934 the POC developed a field in San Patricio County and built an employee camp named Los Encinos near Sinton. Its operational headquarters was located there. In 1952 POC constructed a new office building in Sinton that now belongs to the county and bears a Texas historical marker. Following these successes, the POC drilled in twenty-seven counties, most extensively in Crockett, Duval, San Patricio, Reagan, Upton, and Calhoun. By 1960 it had producers in New Mexico, Wyoming, West Virginia, Pennsylvania, Kentucky, Ohio, Mississippi, Illinois, and Louisiana. In 1947 the POC developed Benedum field and a gas-processing plant in Upton County and established a camp for employees. Susan Peak in Tom Green County also included housing, as did Hallanan Field in Midland, where a regional office was established. POC continued to expand. In 1948 it constructed a pressure maintenance, recycling, and gas-lift plant in Sinton and acquired interest in Melben Oil Company, formed in 1947 to drill off the Texas coast. The POC's holdings included Republic Oil Company, with a refinery in Texas City, the Heyser Gasoline Plant in Calhoun County, and the Plymouth Pipe Line Company. In 1954 POC established an office in Canada and by 1960 had eighty-seven producing wells. In 1956 it acquired control of the Big Lake Oil Company and changed its name to Plymouth. The end of the Suez crisis in 1957 sent the oil industry into recession, and by 1960 the POC was operating at a deficit. The company experienced a decrease in crude production and a reduction in income from refining and marketing operations because of low product prices, increasing oil imports, and heavy charge-offs for abandoned wells and surrendered leaseholds. Even so, the POC conducted exploratory work in Australia, Guatemala, and French West Africa. On January 4, 1962, POC directors announced an agreement to sell virtually all assets to Marathon Oil Company. At the time POC was the longest-operating oil company in West Texas and one of the nation's largest and most successful independent producers.