Mount Ida is a city in and county seat of Montgomery County, Arkansas, United States. Founded in 1842, the city saw a silver boom in the 1880s bring early prosperity and economic development to the area. A slowly growing small town ever since, today, the economy is largely ranching, poultry farming, silviculture, and tourism around Lake Ouachita. It is officially known as the quartz crystal capital of the U.S. and is known worldwide for its quartz deposits. The population had grown to 1,076 by the 2010 census.