Monterrey metropolitan area  The Monterrey metropolitan area refers to the surrounding urban agglomeration of Monterrey, Nuevo León. Officially called "Area Metropolitana de la Ciudad de Monterrey" or AMM, the metropolitan area is the 2nd-largest such area in Mexico. The Monterrey metropolitan area is composed of the municipalities/cities of:  There are three adjacent towns that do not maintain continuous urban development with the core urban area. These towns are considered strategic as the metropolitan area grows and integrates them: