Rochester is a city in Monroe County, New York, south of Lake Ontario in the United States. The Rochester metropolitan area is the second largest regional economy in all of New York State according to the U.S. Internal Revenue, after the New York City metropolitan area. Known as The World's Image Centre, it was also once known as The Flour City, and more recently as The Flower City. It is the county seat for Monroe County.

Rochester's city population is approximately 219,773, making it New York's third most populous city after New York City and Buffalo. It is at the center of a larger Metropolitan Area which encompasses and extends beyond Monroe County and includes Genesee County, Livingston County, Ontario County, Orleans County and Wayne County. This area, which is part of the Western New York region, had a population of 1,037,831 people at the time of the 2000 Census. As of 1 July 2005, this population rose slightly, to 1,039,028.

Rochester was ranked as the sixth 'most livable city' among 379 U.S. metropolitan areas in the 25th edition (2007) of the Places Rated Almanac. The Rochester area also received the top ranking for overall quality of life among U.S. metros with populations of more than 1 million in a 2007 study by Expansion Management magazine. In the same study, Expansion Management rated the area's public schools as sixth best nationwide. In 2010 Forbes rated Rochester as the 3rd best place to raise a family.

The current mayor of Rochester is Robert Duffy, who was previously the city's police chief. In the 2010 general election he was Attorney General Andrew Cuomo's running mate in Cuomo's bid for the governor's office and they won the election.