Objective: Mission of Mercy (MoM) events are scheduled to provide care to populations suffering from urgent needs and inadequate access to dental care in the United States. This study examined individual and county-level characteristics of MoM attendees and the factors associated with changes in the rate of attendance. Methods: Deidentified archival data for MoM events available from the America’s Dentists Care Foundation (2013–2016) were analyzed. Summary statistics were calculated separately for each year. Chi-square test was performed to identify changes in attendance distribution over time. Poisson regression analyses were conducted to test changes in the rate of attendance with and without adjustment for county-level characteristics and history of prior MoM events. Results: Total numbers of attendees at Wisconsin MoM events were 1,560, 1,635, 1,187, and 951 in 2013, 2014, 2015, and 2016, respectively. Attendees were mostly female (>50%) and White (58%–81%), and mean age ranged between 36.5 and 39.2 y. The average travel distance ranged between 27 and 80 miles. Residents of counties where MoM events were held in previous years were more likely to attend another MoM event after adjusting for county distance to current location. After adjusting for dentists-to-population ratio, event history, and county distance to event location, we found that there was no statistically significant change in the rate of attendance from 2013 to 2016. Conclusions: Previous attendees with experience of attending a MoM event in their counties of residence were more likely to attend another MoM event. Higher rates of attendance were associated with shorter travel distances to MoM events. Knowledge Transfer Statement: The Mission of Mercy (MoM) events are promoted by local dental organizations to highlight the issue of access to dental care and bring greater awareness to the problem by providing urgent dental care to populations in need. Through the data-sharing practices and analyses, policy makers, dental health advocates, and program organizers will have a better understanding of the impact and reach of the program. Findings from this study will help to expand program practices, promote efficiency, and aid in the identification of appropriate event locations, innovative strategies, and public policies relevant to addressing access to dental care.