The United States, which was declared measles-free in 2000, has seen a resurgence of measles cases due to importations and outbreaks in undervaccinated communities. From January 1, 2020, to March 28, 2024, the CDC reported 338 confirmed measles cases, with 97 (29%) occurring in the first quarter of 2024, a significant increase over the average number of cases in the same period from 2020 to 2023. The median patient age was 3 years, and 91% of patients were unvaccinated or had unknown vaccination status. The longest transmission chain lasted 63 days. Despite the increase, U.S. measles elimination status was maintained as of the end of 2023 due to the absence of sustained transmission and a well-performing surveillance system. However, the rise in cases in the first quarter of 2024 highlights the need for enhanced vaccination efforts, especially in close-knit and undervaccinated communities, to prevent widespread transmission. The report emphasizes the importance of maintaining high national and local MMR vaccination coverage and rapid case investigation to sustain elimination status.The United States, which was declared measles-free in 2000, has seen a resurgence of measles cases due to importations and outbreaks in undervaccinated communities. From January 1, 2020, to March 28, 2024, the CDC reported 338 confirmed measles cases, with 97 (29%) occurring in the first quarter of 2024, a significant increase over the average number of cases in the same period from 2020 to 2023. The median patient age was 3 years, and 91% of patients were unvaccinated or had unknown vaccination status. The longest transmission chain lasted 63 days. Despite the increase, U.S. measles elimination status was maintained as of the end of 2023 due to the absence of sustained transmission and a well-performing surveillance system. However, the rise in cases in the first quarter of 2024 highlights the need for enhanced vaccination efforts, especially in close-knit and undervaccinated communities, to prevent widespread transmission. The report emphasizes the importance of maintaining high national and local MMR vaccination coverage and rapid case investigation to sustain elimination status.