Despite increasing demand in distance education, relatively little is known about the demographic and socio-economic characteristics as well as basic skill levels of adult distance education participants at the national level in the U.S. This study analyzed the U.S. data from 2012/2014 and 2017 Program for International Assessment of Adult Competencies (PIAAC) to identify baseline determinants of non-formal (i.e., not for a formal credential or degree) distance education among adults aged between 25 and 65 years old. Results showed that higher educational attainment, employment, literacy skills and digital problem-solving skills were positively associated with non-formal distance education participation. As recent distance education is provided predominantly through the internet and digital device, digital skills may be of particular concern. These identified determinants should be reflected in policy interventions to close education gaps. Additionally, the findings of this study are useful for future research that focuses on psychological and behavioral factors. [This paper will be published in "Adult Education Quarterly."]