Mary Louise McLean (maiden name: Thompson) was born on November 14, 1835, in Kentucky. She married Nathaniel Collins McLean on June 1, 1858, and they had at least six children: Elizabeth, born around 1863; Larz, born around 1865; Mary, born around 1866; Natalie, born around 1868; Marshall, born around 1869; and Henriette, born around 1873. They lived in Cincinnati, Ohio, and her husband worked as a lawyer. By 1860, they owned $150,000 of real estate and $27,000 of personal property. They moved to Florence, Minnesota, in the 1870s, and her husband worked as a stock raiser there. By 1900, they were living in Brookhaven, New York. Her husband died on January 4, 1905, and she passed away in Vancouver, Washington, on August 18, 1908.