Context: Initiatives to increase access to treatment for opioid use disorder (OUD) have grown rapidly in response to the opioid epidemic; however, significant gaps in access to treatment remain. Waivered providers often prescribe buprenorphine at rates below their allowed treatment capacity due to a variety of limitations, and some waivered providers do not prescribe buprenorphine. Given this evidence, determining gaps in treatment access based on prescribing capacity alone may not provide the clearest picture of where resources are needed most. This methodology for defining and mapping treatment shortage areas may support more appropriate targeting of resources. Objective: To pilot a methodology to define and map buprenorphine shortage areas for use in planning and evaluation of policy initiatives. Study Design and Analysis: Proportion of individuals with OUD receiving treatment, with treatment provision defined as patients prescribed buprenorphine and treatment need defined as the population with OUD, calculated by multiplying population by an estimated county-level rate of OUD. County-level rates were estimated by developing a logistic regression model based on demographic variables associated with OUD . Maps created using ArcGIS. Datasets: Colorado Prescription Drug Monitoring Program (PDMP), Substance Abuse and Mental Health Services Administration (SAMHSA) waivered provider list, National Survey on Drug Use and Health, American Community Survey. Population Studied: Individuals who have received a buprenorphine prescription, clinicians who have prescribed buprenorphine for OUD, and prescribers waivered to provide buprenorphine in Colorado. Outcome Measures: Proportion of individuals with OUD receiving buprenorphine by county, median miles traveled by patients to obtain buprenorphine by county, number of additional providers needed by county to provide treatment to all patients with OUD if all providers prescribed at half of the most common capacity limit. Results: Availability of buprenorphine treatment is insufficient across Colorado, with variation across counties and regions. Mapping the proportion of individuals with OUD receiving treatment and median miles traveled to receive treatment demonstrate different aspects of inadequate access that do not entirely overlap. Expected Outcomes: This methodology could be replicated in other states and used by policymakers in planning and evaluation of initiatives to address the opioid epidemic.