The Monarch Butterfly Biosphere Reserve is a World Heritage Site containing most of the over-wintering sites of the eastern population of the monarch butterfly. The reserve is located in the Trans-Mexican Volcanic Belt pine-oak forests ecoregion on the border of Michoacán and State of Mexico, 100 km, northwest of Mexico City. Millions of butterflies arrive in the reserve annually. Butterflies only inhabit a fraction of the 56,000 hectares of the reserve from October–March. The biosphere’s mission is to protect the butterfly species and its habitat.
Most of the over-wintering monarchs from eastern North America are found here. Researchers discovered these areas in 1975. Presidential decrees in the 1980s and 2000 designated these still privately held areas as a federal reserve.
Wikipedia https://en.wikipedia.org/wiki/Monarch_Butterfly_Biosphere_Reserve
Coordinates 19°33'10.073" N -100°15'25.504" E
