I am in the process of trying to figure out were my surname origally came from. This is what I have on Thomas McGalin:
In 1834, Thomas McGalin arrived in Texas and requested permission to settle in Zavala's Colony. A grant of one league of land located on the west bank of the Angelina River was given to him in July of 1835. In his letter to Zavala, Thomas stated that his family consisted of eight people. The book of "Residents of Texas 1782-1836" listed Wife- Elizabeth Strother, Children, Mitalda Glass, Elizabeth Glass, Jessie, Alandron and Bertha Ann.
Thomas was in Hinds County, Mississippi in 1830. He moved to Texas in 1835, and in 1838, Thomas McFarland recorded in a journal that he had bought some hogs which had strayed to Cow Creek in present day Newton County from Thonas McGalin. Sometime between 1838-1840, Thomas returned to Mississippi (Pike County, 1840; Amity County, 1850). In 1850 census, Thomas was about 74 years old, so he probably remained in Mississippi until his death. There were more children listed under his name, but I don't know if they were his or his grand-children.