The number of states with comprehensive smoke-free laws in effect increased from zero on December 31, 2000, to 26 states on December 31, 2010. In 2002, Delaware became the first state to implement a comprehensive smoke-free law, followed by New York in 2003, Massachusetts in 2004, and Rhode Island and Washington in 2005. In 2006, comprehensive smoke-free laws went into effect in Colorado, Hawaii, New Jersey, and Ohio, followed by Arizona, DC, Minnesota, and New Mexico in 2007; Illinois, Iowa, and Maryland in 2008; Maine, Montana, Nebraska, Oregon, Utah, and Vermont in 2009; and Kansas, Michigan, South Dakota, and Wisconsin in 2010. The years listed are the years in which the laws took effect; in some cases the laws were enacted in a preceding year. Some state laws were expanded gradually or phased in; in these cases, the year provided is the year when the law first applied to all three of the settings considered in this study. Additionally, while most of these laws were enacted through the state legislative process, Arizona, Ohio, South Dakota, and Washington enacted their laws through ballot measures.