Loyalton is a city in Sierra County, California, United States. At the 2020 census, the population was 740, reflecting a decline of 29 from the 769 counted in 2010. The ZIP code for the community is 96118. The town is near the north extent of State Route 49, which ends at State Route 70 in Vinton. According to Rand-McNally, it is a fifty-mile drive on State Route 49 to the county seat, Downieville.