North County is a region in the northern area of San Diego County, California. It is the second-most populous region in the county, with an estimated population of 869,322. North County is well known for its affluence, especially in Encinitas, Carlsbad, Del Mar, Rancho Santa Fe, Poway and Solana Beach, where house prices range, on average, above $1,000,000. Cities along the 78 freeway have more mixed incomes.

San Diego County, officially the County of San Diego, is a county in the southwestern corner of the U.S. state of California. As of the 2020 census, the population was 3,298,634, making it California's second-most populous county and the fifth-most populous in the United States. Its county seat is San Diego, the second-most populous city in California and the eighth-most populous city in the United States. It is the southwesternmost county in the 48 contiguous United States, and is a border county. It is also home to 18 Native American tribal reservations, the most of any county in the United States.