Olean ( OH-lee-ann) is a city in Cattaraugus County, New York, United States. 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 Western New York.

The city is in the midst of the town of Olean and is located in the southeastern allowance of Cattaraugus County. The population was 13,437 in 2019 per the United States Census Bureau.

The first European in the Place was possibly Joseph de La Roche Daillon, a missionary and entrepreneur from Canada. La Roche reported upon the presence of oil near Cuba, the first petroleum sighting in North America. At that time the Place was a part of the territory of the Wenrohronon or Wenro Indians, an Iroquois speaking people. In 1643, the Wenro tribes became the first victims of a series of brutal conflicts known as the Second Beaver War.

The Place was first arranged by Europeans on the subject of 1765, called by the Indian name Ischua. Officially, this was illegal, as the British had avowed the house in the Allegheny River watershed to be ration of the Indian Reserve after conquering the territory in the French and Indian War two years prior. The surface is a hilly upland, separated into two determined parts by the valley of the Allegheny. The highest points are 500 to 600 feet (150 to 180 m) above the valley. During the American Revolutionary War, the 1779 Sullivan Expedition conventional the first road to what would become Olean, blazing a trail to what is now Kittanning, Pennsylvania along the pathway of what is now New York State Route 16.