abstract:The Monarch Butterfly Biosphere Reserve is a conservation area and World Heritage Site within the wintering grounds of most of the monarch butterflies that migrate from east of the Rocky Mountains for up to 4,000 km south to central Mexico. The reserve is located in the Trans-Mexican Volcanic Belt pine-oak forests ecoregion on the border of Michoacán and Mexico State, 100 km (62 milles), northwest of Mexico City.