California experienced a slight population decline of 0.02%, losing about 9,465 residents from 2024 to 2025. Overall U.S. population growth slowed to below 1%. Five states lost residents, with Vermont seeing the largest decrease. New England states have the oldest populations, while Utah has the youngest. California's median age is 39, with 5.21% under age 5 and over 17.5% aged 65 or older.