Hard Rock is a census-designated place in Navajo County, Arizona, United States. The population was 94 at the 2010 census. The CDP has a total area of 5.92 square miles, all land. As of the 2010 census, there were 94 people living in the CDP: 43 male and 51 female. 37 were 19 years old or younger, 20 were ages 20–34, 17 were between the ages of 35 an…Hard Rock is a census-designated place in Navajo County, Arizona, United States. The population was 94 at the 2010 census. The CDP has a total area of 5.92 square miles, all land. As of the 2010 census, there were 94 people living in the CDP: 43 male and 51 female. 37 were 19 years old or younger, 20 were ages 20–34, 17 were between the ages of 35 and 49, 9 were between 50 and 64, and the remaining 11 were aged 65 and above. The median age was 30.0 years.