Oklahoma was an old line Chicagoland discounter that merged with local competitor Perfect Power in conjunction with selling out to Standard of New Jersey in 1956. Oklahoma was strictly Chicagoland in that era, while Perfect Power had some dealers in Northern Indiana, in addition to its metro area market. Standard of NJ (ESSO) next purchased Gaseteria in 1957, which had just purchased a large part of the old Johnson Oil. Gaseteria also owned Hoosier Pete. Gaseteria had stations throughout Illinois, Indiana, with limited marketing in Iowa, Michigan, northern Kentucky and in the St Louis area. All of these were rebranded Oklahoma in 1957, although there is evidence that the St Louis stuff had been sold before this time. The newly introduced brand Enco was introduced in 1960 and replaced Oklahoma. When Esso and Enco rebranded Exxon in late 1972, part of the former Oklahoma territory retained the Enco name until 1980 before selling out. Richard Small's operation, Cheker, purchased a large part of what remained in 1980 and reintroduced the Oklahoma brand. Cheker, the new Oklahoma and the remnants of Imperial Refineries sold out to the Speedway division of Marathon in the 1980s.