We wanted to quantify how the location in which medical care is delivered in the United States varies with the sociodemographic characteristics and health care arrangements of the individual person.Data from the 1996 Medical Expenditures Panel Survey (MEPS) were used to estimate the number of persons per 1,000 per month in 1996 who had at least 1 contact with physicians' offices, hospital outpatient departments, or emergency departments, hospitals, or home care. These data were stratified by age, sex, race, ethnicity, household income, education of head of household, residence in or out of metropolitan statistical areas, having health insurance, and having a usual source of care.Physicians' offices were overwhelmingly the most common site of health care for all subgroups studied. Lacking a usual source of care was the only variable independently associated with a decreased likelihood of care in all 5 settings, and lack of insurance was associated with lower rates of care in all settings but emergency departments. Generally, more complicated patterns emerged for most sociodemographic characteristics. The combination of having a usual source of care and health insurance was especially related to higher rates of care in all settings except the emergency department.Frequency and location of health care delivery varies substantially with sociodemographic characteristics, insurance, and having a usual source of care. Understanding this variation can inform public consideration of policy related to access to care.