George Phydias Mitchell was born in Galveston on May 21, 1919. At Texas A&M University, he scrambled for tuition money until he started selling gold-embossed stationery to students lonesome for sweethearts back home. He finished first in his class in petroleum engineering and was captain of the tennis team. He worked for Amoco in the oil fields of Texas and Louisiana, before joining the Army Corps of Engineers and overseeing construction projects. After his discharge, he started an oil company with partners, including his brother Johnny. When a Chicago bookie offered the fledgling company a deal for an area north of Fort Worth known as “the wildcatters’ graveyard,” they bit. They quickly drilled 13 successful wells, and bet everything they had to expand their holdings in the area to 300,000 acres. That became the backbone of a company that hit oil or gas on 35 to 40 percent of the 10,000 wells it drilled. In the 1960s, Mr. Mitchell, looking to diversify, bought 66,000 acres of mostly undeveloped real estate within a 50-mile radius of Houston. In 1974 he created The Woodlands, a 27,000-acre forested development 27 miles north of Houston. In 1997, he sold Mitchell Energy’s stake in The Woodlands for $543 million. In his early 20s, Mr. Mitchell met two twin sisters, Cynthia and Pamela Woods. He first dated Pamela but married Cynthia, with whom he created the Cynthia and George Mitchell Foundation. It has given more than $400 million to a variety of causes. Mrs. Mitchell died in 2009. Mr. Mitchell is survived by his sister, Maria Mitchell Ballantyne; three daughters, Pamela Maguire, Meredith Dreiss and Sheridan Lorenz; seven sons, Scott, Mark, Kent, Greg, Kirk, Todd and Grant; 23 grandchildren; and five great-grandchildren. His wife’s twin sister also survives him.