Marin County Sheriff's Office Shared Automated License Plate Reader Information with Outside Law Enforcement Agencies

SAN FRANCISCO—Today, the ACLU of Northern California and the Electronic Frontier Foundation called on the Marin County Sheriff’s Office (MCSO) to investigate and explain how it reportedly shared drivers’ location information with federal and out-of-state law enforcement agencies as recently as 2024 in clear violation of California law and the terms of a 2022 lawsuit settlement.

“It’s alarming that just two years after we settled a lawsuit against the Marin County Sheriff’s Office for illegally sharing millions of drivers’ license plates and locations, the office again provided federal and out-of-state law enforcement agencies direct access to its automated license plate reader database,” said Nick Hidalgo, senior staff attorney at the ACLU of Northern California. “Marin County’s cameras are part of a mass surveillance network that gives police access to a trove of sensitive information they have used to locate and detain immigrants, track people seeking reproductive care, and stalk romantic partners. The sheriff’s office must put robust safeguards in place to ensure that a harmful breach like this doesn’t happen again.”

ACLU NorCal and EFF also filed a Public Records Act request with MCSO seeking proof it is not actively sharing ALPR information with any federal or out-of-state law enforcement agencies.

The Point Reyes Light reported this week that network audit logs show that during the final months of 2024, MCSO shared ALPR information with multiple out-of-state and federal agencies, including 254,131 times in November 2024 alone.

Read the letter.