Health Service Psychologist sits within the Psychologist NUCC taxonomy group and currently counts 906 individual clinicians enrolled in the CMS National Plan and Provider Enumeration System across 49 U.S. states and territories. The NUCC taxonomy is the industry-standard code set CMS uses to classify provider specialties on Medicare and Medicaid claims, and each provider selects their primary taxonomy at NPI enrollment — so this count reflects how many clinicians self-identify their primary practice as Health Service Psychologist rather than a census of every professional who ever trained in the field. Dual-certified practitioners who registered under a different primary code will not appear in this total.

Geographic distribution is uneven across the 49-state footprint. California holds the largest concentration with 89 Health Service Psychologist providers (9.8% of the national total), followed by Massachusetts at 76 (8.4%) and North Carolina at 56. Boston is the top metro for Health Service Psychologist by raw provider count, which tracks population density more than any state-specific licensure pattern — the taxonomy is recognized nationwide through NUCC, not state-by-state. Reading this map carefully matters for patients searching across state lines and for operators planning where to recruit, because thin-coverage regions often reflect training-pipeline constraints rather than unmet clinical demand.

Drill into any state row above to see the full roster of Health Service Psychologist providers in that jurisdiction with address and contact details from NPPES, or pivot to a specific city to narrow further. Important: PlainDoctor is a directory of publicly available CMS government data, not a quality ranking, board-certification verifier, or medical advice. Listing under Health Service Psychologist means only that the provider self-designated this primary NUCC code at enrollment; it does not confirm current board certification, hospital privileges, or fitness to treat any specific condition. Always verify credentials directly through the NUCC taxonomy documentation, the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.