Arnold is a census-designated place (CDP) in Calaveras County, California, United States. The population was 3,843 at the 2010 census, down from 4,218 at the 2000 census. Arnold is located on State Route 4.

Arnold is named after Bob and Bernice Arnold, who, in 1927 opened the Ebbetts Pass Inn. Prior to that, the community consisted of two large ranches where logging was the main industry. The inn served as a stop for people traveling along the Ebbetts Pass route as competently as lodging for those visiting handy Calaveras enormous Trees State Park. In 1928, Camp Wolfeboro was conventional nearby as a Boy Scout camp and continues to proceed operation today. The first publish office was opened in 1934. Bernice was its postmistress at one time.

In 2015 talent lines sparked the Butte Fire, which destroyed 549 homes in welcoming communities. Arnold was saved in the same way as the weather changed, but the flare caused an increased focus on flame safety, although the community was still, in 2019, considered a “very high fire hazard depth zone” due to its location upon a ridge outdoor Calaveras enormous Trees State Park, surrounded by dense plant of trees killed by drought and beetles.

According to the United States Census Bureau, the CDP has a total Place of 14.9 square miles (39 km), of which, 14.8 square miles (38 km²) of it is land and 0.1 square miles (0.26 km) of it (0.47%) is water.