Norovirus is the leading cause of acute gastroenteritis in the United States (1). In April 2020, the incidence of norovirus outbreaks in the United States declined substantially, likely because of implementation of COVID-19-related nonpharmaceutical interventions, such as facility closures, social distancing, and increased hand hygiene (2). Similar declines were observed in other countries (3,4). Norovirus outbreaks in the United States increased rapidly starting in January 2022, approaching prepandemic (i.e., 2012-2019) levels. Norovirus transmission can be prevented by thorough handwashing and proper cleaning and disinfection of contaminated surfaces.In 2012, CDC established the Norovirus Sentinel Testing and Tracking Network (NoroSTAT) to improve timeliness and completeness of surveillance for norovirus outbreaks that occur in the United States. NoroSTAT is a collaboration between CDC and 12 state health departments.* Outbreaks are defined as two or more cases of illness associated with a common exposure. NoroSTAT-participating states report a minimum set of data elements † to the National Outbreak Reporting System § for all confirmed norovirus outbreaks (i.e., outbreaks with two or more laboratory-confirmed norovirus cases) and suspected norovirus outbreaks (i.e., outbreaks with fewer than two laboratory-confirmed norovirus cases) within 7 business days of notification. These states also upload typing information for norovirus-positive outbreak specimens to CaliciNet, ¶ the national norovirus laboratory surveillance network, within 7 business days of receipt of two *