Rochester is a city in Monroe County, New York, south of Lake Ontario in the United States. 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 according to the 2010 census is approximately 210,565, 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 1,054,323 people at the time of the 2010 Census. As of July, 2011, the Census estimates indicated that this population rose to 1,055,278 .

Rochester was one of America's first "boomtowns" and rose to prominence initially as the site of many flour mills located on the Genesee River, then as a major manufacturing hub. Rochester is now an international center of higher education, as well as medical and technological development. The region is known for many acclaimed universities, and several of them (notably the University of Rochester and the Rochester Institute of Technology) are nationally renowned for their research programs. In addition, Rochester has been and continues to be the site of many important inventions and innovations in consumer products. The Rochester area is currently home to corporations such as Kodak, Bausch & Lomb and Xerox that conduct extensive research and manufacturing in the fields of industrial and consumer products. The Rochester metropolitan area is the second largest regional economy in New York State according to the U.S. Internal Revenue Service, after the New York City metropolitan area.