Methamphetamine is a highly addictive central nervous system stimulant. Methamphetamine use is associated with a range of health harms, including psychosis and other mental disorders, cardiovascular and renal dysfunction, infectious disease transmission, and overdose (1,2). Although overall population rates of methamphetamine use have remained relatively stable in recent years (3), methamphetamine availability and methamphetamine-related harms (e.g., methamphetamine involvement in overdose deaths and number of treatment admissions) have increased in the United States* (4,5); however, analyses examining methamphetamine use patterns and characteristics associated with its use are limited. This report uses data from the 2015-2018 National Surveys on Drug Use and Health (NSDUHs) to estimate methamphetamine use rates in the United States and to identify characteristics associated with past-year methamphetamine use. Rates (per 1,000 adults aged ≥18 years) for past-year methamphetamine use were estimated overall, by demographic group, and by state. Frequency of past-year use and prevalence of other substance use and mental illness among adults reporting past-year use were assessed. Multivariable logistic regression examined characteristics associated with past-year use. During 2015-2018, the estimated rate of past-year methamphetamine use among adults was 6.6 per 1,000. Among adults reporting past-year methamphetamine use, an estimated 27.3% reported using on ≥200 days, 52.9% had a methamphetamine use disorder, and 22.3% injected methamphetamine. Controlling for other factors, higher adjusted odds ratios for past-year use were found among men; persons aged 26-34, 35-49, and ≥50 years; and those with lower educational attainment, annual household income <$50,000, Medicaid only or no insurance, those living in small metro and nonmetro counties, and those with co-occurring substance use and co-occurring mental illness. Additional efforts to build state and local prevention and response capacity, expand linkages to care, and enhance public health and public safety collaborations are needed to combat increasing methamphetamine harms.