eHealth provides an important mechanism to connect medically underserved populations with health information, but little is known about gaps in eHealth literacy research in underserved adult populations within the U.S. Between June and July 2013, three systematic literature reviews of five databases were conducted and a subsequent hand search was completed. Identified literature was screened and studies meeting exclusion and inclusion criteria were synthesized and analyzed for common themes. Of the 221 articles critically appraised, 15 met these criteria. Thirty-five of these studies were excluded due to international origin. Of the articles meeting the inclusion criteria, underserved populations assessed included immigrant women, the elderly, low-income, the un- and underemployed, and African-American and Hispanic populations. eHealth literacy assessments utilized included one or two item screeners, the eHEALS scale, health information competence and cognitive task analysis. Factors examined in relation to eHealth literacy included age, experience, overall health literacy, education, income and culture. The majority did not assess the impact of locality and those that did were predominately urban. These data suggest that there is a gap in the literature regarding eHealth literacy knowledge for underserved populations, and specifically those in rural locations, within the U.S.