Reports indicate a geographic effect of socioeconomic inequalities on the occurrence of opioid-related fatal overdoses. This study aims to (1) estimate the rates of opioid-related overdoses, (2) estimate the association of benzodiazepine co-ingestion with opioid-related deaths, (3) estimate associations between socioeconomic indicators and opioid-related deaths, and (4) map the distribution of fatal overdoses, in Orange County (OC), California.An ecologic study was conducted of all opioid- related deaths (1205 total) from 2010 to 2014 obtained from the OC Coroner Division database (1065 OC residents, 55 nonresidents, 85 OC homeless) (analyzed 2016-2017). Rates of opioid overdose, benzodiazepine co-ingestion prevalence, and associations with socioeconomic status (SES; education, poverty, median income) using ZIP code analysis in the residential and homeless communities were calculated.Of 1205 deaths, 904 involved prescription-type opioids, 223 involved heroin, 39 involved both, and 39 not stated; 973 were classified unintentional overdoses, 180 suicides, and 52 undetermined; 49% of cases involved benzodiazepines. Prescription-type opioid and heroin death rates for residents were 5.4/ 100,000 person-years (95% confidence interval [CI]: 5.0-5.8) and 1.2/100,000 person-years (95% CI: 1.0-1.4), respectively. Males, age group 45-54, and Caucasian race had the highest rate (13.6/100,000) of opioid mortality. The highest death rates were seen in homeless adults, at 136/100,000 person-years for prescription-type opioids (95% CI: 99.0-185.5) and 156/100,000 person-years for heroin (95% CI: 116.8-209.5).The burden of prescription-type opioid-related deaths in OC affects all demographics and levels of SES; there is a disproportionately high rate of opioid-related deaths in the OC homeless population.