Picea engelmannii, with common names Engelmann spruce, white spruce, mountain spruce, or silver spruce, is a species of spruce native to western North America, from central British Columbia and southwest Alberta, southwest to northern California and southeast to Arizona and New Mexico; there are also two isolated populations in northern Mexico. It is mostly a high altitude mountain tree, growing at 900 metres (3,000 ft) – 3,650 metres (11,980 ft) altitude, rarely lower in the northwest of the range; in many areas it reaches the alpine tree line.