Measles is a highly contagious disease caused by the measles virus. In Liberia, only one dose of the measles vaccine is given at nine months of age. Liberia had been in a protracted measles outbreak since December 2021. Maryland County is one of the 15 counties in Liberia and administratively reported a measles vaccination coverage of 82% for 2021. On February 2, 2022, a Community Health Promoter reported five suspected cases of measles from Harper City, Maryland County, Liberia. We investigated to verify the outbreak in the county, identify the source and implement control measures.