Carnelian Bay is an unincorporated community on the shore of Lake Tahoe in Placer County, California. Its population was 518 in 2020. Boasting a shoreline glittering with the gemstones of its namesake, Carnelian Bay is a beautiful lakeside community. Carnelian Bay, named in 1860 for the Chalcedony found on its shoreline, has a background steeped in marine, resort and recreational history.