This article examines early voting, an institutional innovation whereby citizens can cast their ballots a time and location other than on election day and at the precinct place. Early voting has been proposed as way to expand the franchise, by making voting more convenient, and extend the franchise, by encouraging turnout among those segments of the population who are unable or unwilling to vote using traditional methods. The article draws on models of voter decision making that conceptualize voting as a choice reached under uncertainty. Voters vary by (a) their willingness to accept uncertainty, (b) their cognitive engagement with the campaign, and (c) their location in an institutional environment that makes early voting possible. We propose a multivariate model of early voting, contingent on a voter's prior levels of political information, level of fixed political beliefs, and political information activity. These are also interacted with the institutional context (laws and procedures that allow early voting). At the descriptive level, we find most of the expected demographic and attitudinal patterns: early voters are older, better educated, and more cognitively engaged in the campaign and in politics. Because national surveys are ill equipped to capture nuanced campaign dynamics, many of the statistically significant relationships disappear in multivariate analyses. Regardless, revealing differences emerge between midterm and presidential election years that allow us to make important inferences about the demographic and participatory characteristics of early voters.