Nashua is a city in Hillsborough County, New Hampshire, USA. As of the 2000 census, Nashua had a total population of 86,605, making it the second largest city in the state after Manchester. As of 2005, the population is estimated to be 87,986.

Built around the now-departed textile industry, in recent decades it has been swept up in southern New Hampshire's economic expansion as part of the Boston region. Nashua was twice named "Best Place to Live in America" in annual surveys by Money magazine. It is the only city to get the No. 1 ranking two times—in 1987 and 1997.