NH 3 From Wikipedia the free encyclopedia NH3, NH-3, NH3 or NH 3 may refer to: Ammonia (chemical formula NH3) National Highway 3 (India) National Highway 3 (India, old numbering) New Hampshire Route 3 New Hampshire's 3rd congressional district Topics referred to by the same termThis disambiguation page lists articles associated with the same title formed as a letter–number combination.If an internal link led you here, you may wish to change the link to point directly to the intended article.