In 1854, she acquired Mount Holly, a 1,699-acre Southern plantation on Lake Washington with outbuildings, livestock and 100 African slaves, from her father. She paid US$100,000 for it. With 100 slaves, she became "among the top 1 per cent of all slaveholders in Mississippi" according to Civil War historian John Y. Simon. After she remarried in 1855, an Italianate mansion was erected on the land. Margaret was critical of the South, which she described as "stagnant." She was a "staunch supporter" of abolitionist politician Abraham Lincoln. She corresponded with Ellen Ewing Sherman, the wife of UnionGeneral William Tecumseh Sherman. She criticized Uncle Tom's Cabin by Harriet Beecher Stowe as "jejune, sentimental, and piffling". She freed her slaves in 1858, prior to the American Civil War. She believed men and women ought to be on the same level. She was described by Civil War historian John R. Brumgardt as "an independent southern woman who disrespected convention." She often took trips to Europe with Caroline Wilson, a friend from Philadelphia.
Personal life
She married James Erwin, the son of Colonel Andrew Erwin, a politician from Tennessee, in 1843. His former wife was Ann Brown Clay, the daughter of Henry Clay, and his brother, John Patton Erwin, was the editor-in-chief of the Nashville Whig newspaper and served as the Mayor of Nashville, Tennessee from 1821 to 1822, and from 1834 to 1835. Moreover, his sister married Thomas Yeatman and later John Bell. They had a son, James William Erwin, who died as an infant, in 1851. Meanwhile, her husband died in 1851. She remarried in 1855 to Dr Charles William Dudley, the son of Kentucky surgeon Benjamin Winslow Dudley. They lived at Mount Holly. They had a son, Charles Wilkins Dudley Jr., who died in 1911 in Cincinnati, Ohio.
Death and legacy
She died on August 28, 1863. She was forty-one years old. She was buried at the Lexington Cemetery in Lexington, Kentucky. In 1981, her great-grandson John Seymour Irwin edited a collection of her letters entitled Like Some Green Laurel: Letters of Margaret Johnson Erwin, 1821-1863, published by the Louisiana State University Press. Irwin transcribed the letters in shorthand, then owned by collector A. S. W. Rosenbach. Their location is now unknown. The book is a biography, based on the letters but also on recollections from other descendants and documents about business and legal transactions he inherited. It contains many factual errors. The Mount Holly mansion burned down on June 17, 2015.