Following the Trueblood et al. v. Washington State DSHS et al. lawsuit, the Trueblood Contempt Settlement Agreement established a multi-phase plan for providing services and treatment to persons in the criminal court system aiming to reduce their likelihood of recidivism. This report fulfills the Settlement Agreement’s requirement for Washington state to “perform an assessment of law enforcement agency co-responder mental health staffing needs to guide future funding requests” in the Phase 1 regions, which include 10 Washington counties. RDA conducted and analyzed data collected from two surveys to assess mental health field response and co-responder program staffing needs in Phase 1 regions. The primary survey represented law enforcement agencies (LEAs) identified by the Washington Association of Sheriffs and Police Chiefs (WASPC) within these regions. A secondary survey represented Behavioral Health Agencies (BHAs) participating in existing co-responder programs that were identified by referral from LEAs. This report presents a detailed analysis of co-responder program staffing and needs, a general description of other issues addressed in the survey, and interpretation of results.