卡马斯县（Camas County, Idaho）是美国爱达荷州中南部的一个县。面积22,021平方公里。根据美国2000年人口普查，共有人口991人 (2005年估计为1,050人)。县治费尔菲尔德 (Fairfield)。

成立于1917年2月6日。县名来自当地一种印第安人和白人殖民者采食的植物块根。

Camas County is a county in the southern portion of the U.S. state of Idaho. As of the 2010 census, the population was 1,117 making it the second-least populous county in Idaho. The county seat is Fairfield. The county was created by the Idaho Legislature on February 6, 1917, by a partition of Blaine County. It is named for the camas root, or Camassia, a lily-like plant with an edible bulb found in the region, which was used as a food source by Native Americans and settlers.