BACKGROUND: Although New York City (NYC) is a hotspot for hepatitis delta virus (HDV) in the United States (US), the epidemiology of HDV remains poorly understood. We aimed to determine HDV testing and positivity rates, calculate prevalence of liver disease progression by HDV status, and assess the association between HDV and community resources. METHODS: We utilized the INSIGHT database, which contains data from the five major NYC health systems, to identify adults with laboratory and/or diagnosis code evidence of hepatitis B virus (HBV) from 2010-2023. HDV positivity included HDV RNA ‚â• 20 IU/mL and/or positive results for HDV Ab, RNA, and Ag. Prevalence of liver-related complications was calculated. Community deprivation index was used to evaluate socioeconomic disparities by HDV testing and positivity status. RESULTS: Here we show that among 106,210 patients with HBV, 5,388 (5.1%) have received HDV testing; 294 (5.5%) are HDV + . HDV-tested individuals are more likely to be older and Asian, receive comprehensive HBV care, and have more community resources. HDV+ individuals are more likely to be female, White, and have higher prevalence of liver disease progression. CONCLUSIONS: HDV is undertested and under-detected, even in a high-prevalence US region. Early linkage to treatment is essential given high rates of liver disease progression.