On November 7, 1975, by Virtue of PRESIDENTIAL DECREE No. 824, Marikina was detached from Rizal and became part of the newly created Metropolitan Manila.
Section 2. Territorial Jurisdiction. The Commission shall have jurisdiction over the cities of Manila, Quezon, Pasay and Caloocan and the municipalities of Makati, Mandaluyong, San Juan, Las Piñas, Malabon, Navotas, Pasig, Pateros, Parañaque, Marikina, Muntinlupa, and Taguig in the province of Rizal; and the municipality of Valenzuela, in the province of Bulacan, all of which together shall henceforth be known as Metropolitan Manila. – Source