Ellen Margaret “Nellie” Gilliam Day was the daughter of Oregon Country pioneers, born in Dallas, Polk County, Oregon, in 1854. Her family moved to Walla Walla in 1859. She was an educator and a journalist. Nellie defeated her male opponent to serve as Walla Walla County School Superintendent 1887-1889 and became the first female employee at the Walla Walla Evening Bulletin in 1906. She advanced from proof reader to society editor, and wrote many articles for Up-to-the-Times Magazine, a monthly publication covering the Inland Empire, through the 1920s. Nellie will visit Fort Walla Walla Museum from the year 1918.

Nellie Gilliam Day is portrayed by Susan Matley.