Emerald Lake Hills or Emerald Hills is a census-designated place and neighborhood in unincorporated San Mateo County, in the state of California, United States. Situated among oak-studded hills between Woodside, Redwood City, and San Carlos roughly bounded by Edgewood Road, Alameda de las Pulgas, Farm Hill Boulevard, and Interstate 28…Emerald Lake Hills or Emerald Hills is a census-designated place and neighborhood in unincorporated San Mateo County, in the state of California, United States. Situated among oak-studded hills between Woodside, Redwood City, and San Carlos roughly bounded by Edgewood Road, Alameda de las Pulgas, Farm Hill Boulevard, and Interstate 280. The population was 4,406 at the 2020 census and the per-capita income was $68,966, making it the 22nd wealthiest place in California and the 82nd highest income places in the United States