A Metropolitan Statistical Area (MSA) is a geographic region that consists of a densely populated urban center and its surrounding areas, which are economically and socially connected. MSAs are defined by the U.S. Office of Management and Budget and typically include one or more counties that are linked to the urban core through commuting patterns. MSAs are used for statistical purposes, helping to analyze demographic and economic data. They can vary in size, with some covering large cities like New York City and others encompassing smaller towns. This classification helps in understanding regional trends and planning for infrastructure and services.