Final answer:
Individuals between the ages of 18 and 29 are the least likely to vote in national elections due to factors such as low political engagement, lack of trust in the electoral system, and dislike of candidates.
Step-by-step explanation:
According to various studies and data, the category of the U.S. population that is least likely to vote in national elections is individuals between the ages of 18 and 29. Research conducted by Harvard University's Institute of Politics has shown that young adults in this age group have lower political engagement and voter turnout compared to older age groups. Factors such as lack of trust in the electoral system, dislike of candidates, and low awareness of government involvement contribute to the lower likelihood of voting among young adults.
Learn more about voter turnout