Emotional public events, relative to non-emotional ones, are typically remembered more accurately, more vividly, and with higher confidence. However, most of the previous studies on this issue focused on negative public events. Thus, less is known about long-term memories for positive public events. To address this issue, we assessed individuals’ memory for the time when they learned the results of the United Kingdom’s 2016 Referendum on its European Union (EU) membership. Participants included British participants who voted to leave the EU in the referendum and found the event highly positive, British participants who voted to remain in the EU and found the event highly negative, and U.S. participants who did not vote and found the event neutral. Data from a total of 851 participants were assessed across four time points over the course of 16 months. The results showed that differences in memory between the Remain voters and the Leave voters emerged over time. Relative to the Leave voters, the Remain voters maintained higher levels of memory consistency with time; these results suggest that they maintained a more accurate long-term memory for the event. In contrast, the Leave voters maintained higher levels of memory confidence over time than the Remain voters, suggesting that they have over-confidence in their memory. Our results suggest that memories for the same public event can be remembered differently depending on whether individuals find the event positive or negative.