Roy Rogers wasn't always Roy Rogers and one of Hollywood's most famous cowboys didn't grow up on a western ponderosa either. In 1920 he is enumerated as eight year old Leonard Sly in Scioto County, Ohio, with his family (see the complete enumeration). The Ohio native did not move to California until after the 1930 census enumeration.
Those who want to search for less well-known relatives in the 1920 census can do so at Ancestry.com--just make certain you know their correct name and if that name is common, have an idea of where they would be living and others who would be enumerated in the same household.