Mongolia is an historical community in Markham, Ontario centred on 10th Line (Reesor Road) and Elgin Mills Rd.

The hamlet lies completely within the expropriated federal Pickering Airport lands and also within the proposed boundaries of a future national Rouge Park.

During the Upper Canada Rebellion, William Lyon Mackenzie's troops apparently designated a large elm tree in Mongolia on Elgin Mills/ 18th Ave, between concessions 9 and 10 as a rallying point.

Beside the original schoolhouse was a Wesleyan Methodist church which existed for only short time; it was torn down and moved to concession 9 in 1877 and land now Bushwood Golf Course.

[3] In March 1972, the federal government announced plans for a future international airport on the Pickering side of the York-Durham Line.