NASHUA, a city of the United States, in Hillsborough county, New Hampshire, on hilly ground at the confluence of the Merrimac and the Nashua, 40 miles north-north-west of Boston by the Boston, Lowell, and Nashua Railroads. In 1803 the site was "a sandy plain covered with pine trees " ; but after the formation of the Nashua Manufacturing Company in 1823 the village rapidly grew up, and by 1853 it was incorporated as a city. Its population increased from 10,543 in 1870 to 13,397 in 1880. The water-power of the Nashua river being rendered easily available by means of a canal 3 miles long and 8 feet deep, constructed in 1825-26, a great variety of industrial establishments are situated in the city. Besides the sheetings, shirtings, prints, and flannels manufactured by the original Nashua company and its younger rivals, iron goods, locks, edge tools, bedsteads, carpets, shuttles, bobbins, shoes, cards, glazed paper, are all produced on a large scale.