Sunoco got its start on March 27, 1886, when Joseph Newton Pew and Edward O. Emerson, partners in The Peoples Natural Gas Company in Pittsburgh, Pennsylvania, made a bold move to diversify their business. Looking to the promising new oil discoveries in Ohio and Pennsylvania, the partners paid $4,500 for two oil leases near Lima, Ohio. Within a few years the company had acquired pipelines, leases, storage tanks -- and was emerging as one of Ohio's leading suppliers of crude oil. On March 17, 1890, it became The Sun Oil Company of Ohio and was producing, transporting and storing oil as well as refining, shipping and marketing petroleum products. Through the purchase of the Diamond Oil Company in 1894, Sun acquired a refinery in Toledo, Ohio, and began operations there in 1895. The partnership ended in 1899, when Mr. Pew bought out Mr. Emerson's interest.
By 1901, the company was incorporated in New Jersey as Sun Company and turned its interest to the new Spindletop field in Texas. Pew's sons, J. Howard Pew and Joseph N. Pew, Jr. would take over the company after their father's death.
With a growing portfolio of oil fields and refineries, Sun opened its first service station in Ardmore, Pennsylvania in 1920. In 1922, it changed its name back to Sun Oil Company and, in 1925, it became a public company via an initial public offering on the New York Stock Exchange. Sunoco ranked 39th among United States corporations in the value of World War II production contracts. Sun expanded internationally following the war. Its first Canadian refinery was built in 1953 in Sarnia, Ontario, home to a burgeoning new petrochemical industry. Sun established a facility at Venezuela's Lake Maracaibo in 1957, which produced over a billion barrels before the operation was nationalized in 1975.