the epic withdrawal of the Chinese communists from SE to NW China in 1934-5, over a distance of 9,600 km (6,000 miles). 100,000 people, led by Mao Zedong, left the communist rural base after it was almost destroyed by the Kuomintang; 20,000 people survived the journey.
Long March in other Oxford dictionaries
Definition of Long March in the US English dictionary