Contra Costa County Library

The Contra Costa County Library System provides public library services across Contra Costa County, California. Its core operations include facilitating physical book checkouts using library cards at its 26 branches and offering digital resources through platforms like Discover & Go and Overdrive. The system serves the general public within the county, maintaining physical locations while supporting online access to materials and services. Its primary market is the resident population of Contra Costa County seeking informational, educational, and recreational resources.

The library system operates 26 physical branches, indicating a significant county-wide footprint. A notable distinguishing attribute revealed through incident response is its operational resilience and data handling practices. During a ransomware attack in January 2020, the library maintained partial functionality for physical checkouts and ensured virtual platforms remained operational despite network outages affecting internal systems. The library explicitly stated it does not store Social Security numbers or credit card data and had previously purged driver's license details from its systems. Officials confirmed no evidence of patron personal data compromise during the incident, attributing this partly to the unaffected patron database server. The organization collaborated with law enforcement and IT experts to investigate the attack while restoring services.