Pine Hills is a census-designated place in Humboldt County, California, United States, adjacent to Eureka. The population was 3,131 at the 2010 census, up from 3,108 at the 2000 census. Pine Hills includes areas like Ridgewood and areas as far south as the small neighborhood of Elk River. An area near this artificial census construct is called Pine Hill by Loca…Pine Hills is a census-designated place in Humboldt County, California, United States, adjacent to Eureka. The population was 3,131 at the 2010 census, up from 3,108 at the 2000 census. Pine Hills includes areas like Ridgewood and areas as far south as the small neighborhood of Elk River. An area near this artificial census construct is called Pine Hill by Local government agencies and officials. Pine Hill is a much smaller area than "Pine Hills" and as defined by local agencies is actually within an adjacent CDP named Bayview.