Parents were Samuel Patterson Magill (1783-1865)and Nancy Shackleford.

James Patterson6 Magill (Samuel5, James4, John3, William2, Robert1) came to Texas, and while on the road from Houston to Austin the first battle of the Mexican War occurred on the Rio Grande River. Shortly after arriving in the state, he joined Capt. Henry E. McCulloch's company of State Rangers, which had been mustered into the United States service. Magill was elected a 2nd Lt. and served until the close of the struggle. After the close of hostilities Magill spent two years in his native state of Kentucky, and while there was married in 1846. He returned to Texas and settled in what later became Burnet County. Here he remained for 20 years after the organization of the county. He was a Mason in Kentucky and served as secretary and worshipful master of the Burnet Lodge in 1850. He devoted much of his time while living in Burnet to the State ranger service in 1850. He served as County Clerk between 1854 and 1861 at Burnet County, Texas.

He appeared on the census of 1860 at Burnet County, Texas;

He represented the Counties of Burnet, Llano, and San Saba in the Texas Legislature in 1863 at Texas. He was wounded in the lower left side by an arrow, in a fight with Indians, but as it was winter and he was heavily clad, the arrow passed through 32 layers of clothing and ranged backward to the backbone in 1865 at Burnet County, Texas. He purchased 800 acres of land, moved there, and served one term as county commissioner, during which time the court house in Georgetown was built in 1869 at Leander, Williamson County, Texas.

He appeared on the census of 1870 at Burnet County, Texas;

He appeared on the census of 12 Jun 1880 at Precinct 2, Williamson County, Texas;