Lake County had the highest fentanyl overdose death rate of any California county in 2025, according to preliminary figures from the California Department of Public Health.
Twenty-four Lake County residents died of overdoses involving fentanyl last year, the state’s overdose surveillance dashboard shows. That’s 40.9 deaths per 100,000 residents, a rate the state adjusts to the age makeup of the U.S. population in 2000. It’s nearly four times the statewide rate of 10.4.
Humboldt County, at 40.0, and Del Norte County, at 39.9, were close behind. The dashboard lists each rate with a 95% confidence range, a low and a high bound, and the ranges for the three counties overlap.
Counting every drug, Lake’s 2025 rate was 99.2 overdose deaths per 100,000 residents, also the highest in the state and about five times the statewide rate of 20.0. The dashboard counts 66 Lake County overdose deaths in 2025.
The state updated the dashboard Aug. 20. Its death figures are final through 2024 and preliminary for 2025.
Methamphetamine in most Lake deaths
Most of Lake County’s overdose deaths in 2025 involved a stimulant. The dashboard counts 47 Lake deaths involving methamphetamine or another psychostimulant, a rate of 70.0 per 100,000, about six times the statewide rate of 11.4. Seventeen deaths involved both an opioid and a stimulant.
A single death can involve more than one drug, so the counts by drug overlap and don’t add up to the total.
A rise after a drop
Fentanyl deaths in Lake County climbed from three in 2018 to 26 in 2021, a rate of 43.3 per 100,000. The rate stayed near that level in 2022 and 2023, then fell to 24.7 in 2024, with 17 deaths. The preliminary 2025 count of 24 brings the rate back to 40.9.
Statewide, the fentanyl death rate rose to 19.1 in 2023, then fell to 12.9 in 2024 and to 10.4 in the preliminary 2025 figures.
Lake’s rate for all overdose deaths has stayed high throughout. It was 97.3 per 100,000 in 2021, with 66 deaths, and 76.6 in 2024, with 61. The state’s County Health Status Profiles, a separate ranking of county death rates, put Lake worst of California’s 58 counties for drug overdose deaths for 2021 through 2023, with 175 deaths over the three years.
Mendocino’s numbers fell
Mendocino County’s fentanyl death rate moved the other way. In 2021, 40 Mendocino County residents died of fentanyl overdoses, a rate of 49.1 per 100,000, second in the state. The rate fell each year after that. The preliminary 2025 count is 11 deaths, a rate of 13.7.
Mendocino’s overall overdose death rate fell from 76.8 per 100,000 in 2021, with 72 deaths, to 41.8 in 2025, with 40.
In Sonoma County, 53 residents died of fentanyl overdoses in 2025, a rate of 12.2 per 100,000. Napa County counted five, and the dashboard flags its rate as possibly unstable.