Merced County is located in the Central Valley of the U.S. state of California. The county seat is Merced. The county was formed in 1855 and named after the Merced River or El Río de Nuestra Señora de la Merced (River of Our Lady of Mercy); named in 1806 by an expedition, headed by Gabriel Moraga. The county has a total area of 1,972 mi²,98% of it is land and 2% of it is water. As of the census of 2000, there were 210,554 people, 63,815 households, and 49,775 families residing in the county. The population density was 109/mi². The median age was 29 years.