What is already known on this topic? Quitting smoking is beneficial to health at any age, and cigarette smokers who quit before age 35 years have mortality rates similar to those of persons who never smoked. What is added by this report?During 2001–2010, the proportion of adult cigarette smokers who had made a quit attempt in the past year increased significantly in 29 states and the U.S. Virgin Islands. During 2011–2013, the proportion who had made a quit attempt increased in Hawaii and Puerto Rico and decreased in New Mexico. In 2013, the proportion who had made a quit attempt ranged from 56.2% (Kentucky) to 76.4% (Puerto Rico and Guam) with a median of 65.9%, and was generally lower in older age groups. What are the implications for public health practice? Continued implementation of effective evidence-based public health interventions can reduce the health and costs impacts of smoking-related disease and death and accelerate progress toward meeting the Healthy People 2020 target to increase to ≥80% the proportion of U.S. adult cigarette smokers who made a quit attempt in the past year. These interventions include increasing the price of tobacco products, implementing comprehensive smoke-free laws, conducting educational mass media campaigns, and providing insurance coverage for all effective cessation treatments as well as access to quitlines.