What year was the immigrant from Hongdong County, Shanxi Province?

The population migration in Hongdong County of Shanxi Province began in the sixth year of Hongwu in Ming Dynasty (A.D. 1373) and lasted more than ten times in the fifteenth year of Yongle in Ming Dynasty (A.D. 14 17), which was an important part of the great migration in the early Ming Dynasty. Because the place where the immigrants left was near the big locust tree in Hongdong County, Shanxi Province, there were also names such as Hongdong immigrant, big locust tree immigrant, Hongdong big locust tree immigrant and ancient locust tree immigrant in the early Ming Dynasty.