It is important to understand the socioeconomic and medical determinants of subjective cognitive decline (SCD) at a population level in the United States. The primary outcomes are state-level rates of SCD and SCD-related functional impairment in adults aged ≥ 45, both measured in the Behavioral Risk Factor Surveillance System from 2016 to 2022. The exposures are state-level rates of poverty, unemployment, homelessness, college education, racial and ethnic minorities, uninsurance, smoking, hypertension, diabetes, and obesity as well as household income and physician density. The strongest state-level associations with rates of SCD were the prevalence of diabetes (rho=0.64), hypertension (rho=0.59), and poverty (rho=0.58; all p<0.001), and with SCD-related functional impairment were prevalence of poverty (rho=0.71), diabetes (rho=0.68), and hypertension (rho=0.53; all p<0.001). This study highlights critical links between SCD and socioeconomic and medical determinants in adults aged ≥ 45 in the United States, including the prevalence of poverty, diabetes, and hypertension. State-level analysis reveals socioeconomic and medical risk factors for subjective cognitive decline (SCD) at a population level. The prevalence of poverty is a critical contributor to the state-level prevalence of SCD. The prevalence of diabetes and hypertension are also strong state-level determinants of SCD. Addressing the burden of cognitive decline at the population level necessitates targeting socioeconomic and medical factors.