This user guide provides a detailed explanation of the Unmet Need Score (UNS) and the Service Area Needs Assessment Methodology (SANAM) used by the Health Center Program to assess unmet needs for primary and preventive health care services. The guide outlines the structure of the UNS, which quantifies unmet needs based on access to care, barriers to services, and population health status. It describes the methodology's key features, including scoring at the ZIP Code level and the use of public data to create comprehensive profiles of service areas. The document also explains the different measures included in the UNS, their weights, and how to interpret their values. Additionally, it provides guidance on calculating the UNS for various regions, including U.S. Territories and Freely Associated States. Appendices include detailed methodologies and examples for calculating the UNS, as well as a framework for defining need and selecting measures.