Rochester is a city in and the county seat of Monroe County, New York, United States. It is the fourth-most populous city in New York, with a population of 211,328 at the 2020 census. The Rochester metropolitan area in Western New York has an estimated 1.06 million residents and is the 54th-largest metropolitan area in the U.S. Throughout its history, Rochester has acquired several nicknames based on local industries; it has been known as "the Flour City" and "the Flower City" for its dual role in flour production and floriculture, and as the "World's Image Center" for its association with film, optics, and photography.
The city was one of the United States' first boomtowns, initially due to the fertile Genesee River valley which gave rise to numerous flour mills, and then as a manufacturing center, which spurred further rapid population growth. Rochester has also played a key part in US history as a hub for social and political movements, especially abolitionism, and the women's rights movement.