Maros-Torda was an administrative county (comitatus) of the Kingdom of Hungary. Its territory is now in central Romania (eastern Transylvania). Its county seat was Marosvásárhely (Romanian: Târgu Mureș).
Maros-Torda county shared borders with the Hungarian counties Kolozs, Beszterce-Naszód, Csík, Udvarhely, Kis-Küküllő and Torda-Aranyos. The river Mureș/Maros flows through the county. Its area was 4188 km² around 1910.
Maros-Torda county was formed in 1876 on the territory of the Székely settlement Marosszék and part of Torda region. In 1920 after the Treaty of Trianon, the county became part of Romania except after the Second Vienna Award, between 1940–1944 during World War II. Its territory lies in the present (larger) Romanian county Mureș.
In 1900, the county had a population of 197,618 people and was composed of the following linguistic communities:
Total: