The majority of these papers are Mary Day Lanier's incoming letters either from her husband Sidney or about him after his death. Mary's letters to Sidney are in Series 2 and to his brother Clifford in Series 1. There are letters from other family members such as her brother-in-law Clifford, her father Charles Day and her brother Henry. Henry was attached to General Breckinridge's corps and set three letters (1863) describing army life including a map of the engagement at Lookout Mountain outside Chattanooga. Other frequent correspondents were Gibson Peacock, Charles Scribner's Sons, John Banister Tabb, Marie Taylor, and William Hayes Wood. Francese L. Turnbull returned the letters Mary Day and Sidney Lanier wrote to her. These letters (1879-1915 approximately 100 items) are in this series with the letters the Turnbulls wrote to Mary Day.

There are a few of Mary's writings as well as manuscript and printed copies of The Laurel: An Ode (1889) written to Mary Day Lanier by Richard Hovey. There is also a poem by her son Robert entitled "The Master Color-Scheme."