Mary Lucile Pepoon was born on 8 Aug. 1887 in Illinois, the daughter of physician and botanist Herman Silas Pepoon. After graduating from Chicago’s Lake View High School and obtaining her nursing credentials in 1909 from the city’s German American Hospital (later renamed Grant Hospital), she was a school nurse for Chicago’s Department of Health for seven years (writing a short statement about ethics for the school nurse). She headed for France on 19 May 1917 on the SS Mongolia but when the Mongolia‘s guns misfired and killed two nurses, the ship turned back to New York to make provisions for the dead and send injured nurse Emma Matzen to the hospital. It re-embarked on May 22, was attacked by a submarine on June 1, arrived in Cornwall on June 2, and was greeted by King George V and Queen Mary. The personnel set off for France on June 11.
In Etaples, Pepoon served at Base Hospital No. 12 (dubbed “the Northwestern Unit,” as many of the medical officers and enlisted men were from Northwestern University). It was reported that her dedication to her nursing duties continued even while she was running a temperature, until she became more seriously ill in June 1918. In November 1918 she died (attributed variously to trench fever, septicemia, and endocarditis) and was buried with full military honors in Somme American Cemetery. She received a posthumous Red Cross Medal (accepted by her father). In 1921, a tablet was placed in her memory in Chicago’s Independence Park (located near her family home). As the Chicago Tribune notes, the memorial boulder to Pepoon was rededicated in May 1966 at Graceland Cemetery (see this photo of the Pepoon memorial boulder, ca. 1956).
As this National Park Service report in the National Archives makes clear, the Independence Park District purchased Herman Silas Pepoon’s property on West Byron Street in 1930 to enlarge Independence Park.