Oliver Winfield Killam, oilman and town founder, was born on April 27, 1874, in Lincoln County, Missouri, the oldest of seven children of Winfield and Katherine (Macgruder) Killam. At the age of eighteen he entered La Grange College in La Grange, Missouri, where he excelled in football. In 1896 he graduated from the law department of the University of Missouri. Soon thereafter, he moved to Joplin to establish a law practice, but after only six months he abandoned law in order to work in zinc mining. With no experience or knowledge of the industry, Killam began working as a laborer. In 1898, only six months later, he became manager. In the spring of 1902 he met and married Harriet (Hattie) Smith, the daughter of a prominent physician in South West City, Missouri; they had three children. The couple moved to Grove, Oklahoma, where Killam established a successful lumber and mercantile business. In 1907 he became politically active as a strong advocate of Oklahoma statehood. In 1910 he won a seat in the Oklahoma House of Representatives, where he remained for four years. Also in 1910 he established Locust Grove, Oklahoma. In 1914, Killam was elected to the Oklahoma Senate, where he served for four years and befriended the first governor of the state, Charles N. Haskell. In 1919, Haskell suggested to Killam the idea of moving to South Texas to look for oil. Killam sold his business and property, abandoned his promising political career, and, in the spring of 1920, moved to Laredo.
He secured an oil lease on the Hinnant Ranch in Zapata County. After erecting his first oil derrick, he purchased a rig and began drilling. Mirando Oil Company Hinnant No. 1, as it was called, proved a failure. Killam's second attempt, Hinnant No. 2, was lost because of bad casing. Success finally came with No. 3, on April 17, 1921. At 1,461 feet the well came in and pumped about twenty barrels a day. It became the first commercial oil well south of San Antonio and encouraged others to join in exploration. In 1921, with Colon Schott of Cincinnati, Ohio, Killam developed the Schott oilfield, just south of the fledging town of Mirando City, which he had established. Killam's biggest and most successful gusher, Schott No. 2, produced 300 to 400 barrels of oil daily, plus several million cubic feet of natural gas. Photographs of the well flowing wild, plus accounts of its success in newspapers all over the state, encouraged the South Texas oil boom of the 1920s. After the development of the Schott field many South Texas cattle ranchers began leasing large tracts of land to explore for oil, and Mirando City soon became the center of the fast-growing South Texas oil business. Killam next established the Texpapa Pipe Line Company in order to carry the oil to tank farms or railroad tank cars. In 1923 he established the Misko Refineries at Mirando City in order to capitalize further on his investment.
During the 1930s he served as president of both the Laredo Chamber of Commerce and the South Texas Chamber of Commerce. He was named "King Petrol" at the Oilmen's Jubilee by the oil operators of the Laredo district on July 4, 1937. In 1956 he was named Outstanding Citizen of South Texas by members of the Washington's Birthday Celebration Association of Laredo. In only a few short years, Killam became one of the best-known wildcatters in South Texas. He died at the age of eighty-four on January 1, 1959.