OBJECTIVE Suicidal thoughts and behaviors are important public health concerns in the United States. In 2008, a total of 36,035 persons died as a result of suicide, and approximately 666,000 persons visited hospital emergency departments for nonfatal, self-inflicted injuries. State-level data on suicide-related issues are needed to help establish program priorities and to evaluate the effectiveness of suicide prevention strategies. Public health surveillance with timely and consistent exchange of data between data collectors and prevention program implementers allows prevention program practitioners to implement effective prevention and control activities. METHODS January 1, 2008-December 31, 2009. METHODS The National Survey on Drug Use and Health (NSDUH) is a national- and state-level survey of a representative sample of the civilian, noninstitutionalized U.S. population aged ≥12 years. NSDUH collects data on health-risks related to the use of illicit drugs, alcohol, and tobacco; initiation of substance use; substance use disorders and treatment; health care; and mental health. This report summarizes data on responses to questions concerning suicidal thoughts and behaviors contained in the mental health section among sampled persons aged ≥18 years in all 50 states and the District of Columbia. This report analyzes data on the prevalence of suicidal thoughts, planning, and attempts by age, sex, race/ethnicity, and state from 92,264 respondents in the 2008 and 2009 NSDUH. RESULTS Prevalence estimates of suicidal thoughts and behaviors varied by sociodemographic factors, region, and state. During 2008-2009, an estimated 8.3 million (annual average) adults aged ≥18 years in the United States (3.7% of the adult U.S. population) reported having suicidal thoughts in the past year. The prevalence of having suicidal thoughts ranged from 2.1% in Georgia to 6.8% in Utah. An estimated 2.2 million (annual average) adults in the United States (1.0% of the adult U.S. population) reported having made suicide plans in the past year. The prevalence of reports of suicide planning ranged from 0.1% in Georgia to 2.8% in Rhode Island. An estimated 1 million (annual average) adults in the United States (0.5% of the U.S. adult population) reported making a suicide attempt in the past year. The prevalence of reports of suicide attempts ranged from 0.1% in Delaware and Georgia to 1.5% in Rhode Island. The prevalence of suicidal thoughts, suicide planning, and suicide attempts was significantly higher among young adults aged 18-29 years than it was among adults aged ≥30 years. The prevalence of suicidal thoughts was significantly higher among females than it was among males, but there was no statistically significant difference for suicide planning or suicide attempts. CONCLUSIONS The findings in this report indicate that substantial variations exist at the regional and state level in the prevalence of adults who had suicidal thoughts, made plans to attempt suicide, and attempted suicide in the past year. Geographic differences in prevalence might be attributable to selective migration, sociodemographic composition of the population, or the local social environment (e.g., social relationship indicators such as divorce rates or resources for access to health care). These findings emphasize the importance of continued surveillance to collect locally relevant data on which to base prevention and control activities. CONCLUSIONS A better understanding of the patterns of the precursors to suicide is crucial to planning and evaluating a broad spectrum of suicide prevention efforts. These results can be used by state health departments and federal agencies to measure progress toward achieving national and state health objectives (e.g., those outlined in the National Strategy for Suicide Prevention). Continued surveillance is needed to design, implement, and evaluate public health policies and programs that can lead to a reduction in morbidity and mortality related to suicide-related thoughts and behaviors. Possible strategies to implement could include universal strategies (e.g., public education campaigns that focus on improving recognition of suicide risk) and indicated strategies (e.g., cognitive-behavioral therapy) that address the needs of persons exhibiting certain risk factors (e.g., persons who have made suicide attempts).