During March 29-April 25, 2020, emergency department (ED) visits in the United States declined by 42% after the declaration of a national emergency for COVID-19 on March 13, 2020. Among children aged ≤10 years, ED visits declined by 72% compared with prepandemic levels (1). To assess the continued impact of the COVID-19 pandemic on EDs, CDC examined trends in visits since December 30, 2018, and compared the numbers and types of ED visits by patient demographic and geographic factors during a COVID-19 pandemic period (December 20, 2020-January 16, 2021) with a prepandemic period 1 year earlier (December 15, 2019-January 11, 2020). After an initial decline during March-April 2020 (1), ED visits increased through July 2020, but at levels below those during the previous year, until December 2020-January 2021 when visits again fell to 25% of prepandemic levels. During this time, among patients aged 0-4, 5-11, 12-17, and ≥18 years, ED visits were lower by 66%, 63%, 38%, and 17%, respectively, compared with ED visits for each age group during the same period before the pandemic. Differences were also observed by region and reasons for ED visits during December 2020-January 2021; more visits during this period were for infectious diseases or mental and behavioral health-related concerns and fewer visits were for gastrointestinal and upper-respiratory-related illnesses compared with ED visits during December 2019-January 2020. Although the numbers of ED visits associated with socioeconomic factors and mental or behavioral health conditions are low, the increased visits by both adults and children for these concerns suggest that health care providers should maintain heightened vigilance in screening for factors that might warrant further treatment, guidance, or intervention during the COVID-19 pandemic.