Olean is the largest city in Cattaraugus County and serves as its financial, business, transportation and entertainment center. It is one of the principal cities of the Southern Tier region of New York. It's population is 13,711 and is bordered by the Allegheny River to the south and Interstate 86, the Southern Tier Expressway to the north. The Olean Creek joins the Allegheny River in the city, and the hills surrounding the city are historical centers for oil production, although most of the wells are just stripper wells nowadays, producing a few barrels a day.