NH4

NH4 or NH 4 or NH-4 may refer to:


 * Ammonium, the cation in chemistry
 * National Highway 4 (India), new numbering for a National Highway in India
 * National Highway 4 (India, old numbering), a major National Highway in western and southern India
 * New Hampshire Route 4, a short state highway located in eastern Strafford County, New Hampshire, United States