Background: Alcohol use constitutes a serious public health issue for young people in the United States. Although the national trend in underage drinking is encouraging, this issue remains a concern. Method: Combined 2012–2014 National Survey on Drug Use and Health national, regional, state-level, and substate-level estimates of past month binge drinking among people aged 12 to 20 were analyzed. Results: Underage binge drinking estimates vary extensively among census regions, within each state, and throughout the nation. Among the substate regions, past month underage binge drinking estimates ranged from 8.37 percent in Shelby County (Tennessee) to 42.39 percent in Ward 2 (District of Columbia). Compared with the estimate from 2010-2012, the estimate of past month underage binge drinking in 2012–2014 was lower in the nation as a whole (15.87 percent in 2010–2012 vs. 14.44 percent in 2012–2014). Eighteen states plus the District of Columbia experienced a statistically significant decrease from 2010-2012 to 2012–2014 in the rate of past month underage binge drinking, while the remaining 32 states experienced no change in past month underage binge drinking. Conclusion: Highlighting the percentage of youths engaging in underage binge drinking at state and substate levels can help policymakers inform their assessments of substance abuse needs in their communities.