The 50 wealthiest U.S. counties by average household income show California and Virginia leading, with Virginia having nine wealthy counties. Top counties include San Mateo, Marin, and Santa Clara in California, and Falls Church and Loudoun in Virginia. Average household incomes range from about $156,000 to over $216,000, with typical home values varying widely, from around $522,000 to nearly $4.8 million.