Rose Greenhow was the most famous spy in the Civil War, but probably accomplished very little more than warning the Confederates that the Union was advancing on Manassas, sending messages on 9 July and on 16 July 1861. Pinkerton arrested her on 23 August. She was initially kept under arrest at her house, but after a letter she wrote was published in Richmond and republished in the North, she was moved to the Old Capital Prison, with her eight-year-old daughter Rose (on 18 January 1862). There a private in the 91st PA observed an incident involving her daughter and a child named Harry (letter). She was deported to the Confederacy on 31 May 1862. The Confederate government sent her on a diplomatic mission to England and France. She was drowned on the return voyage, on 30 September 1864, when the British blockade runner (the Condor) she was on ran aground and she attempted to land in a small boat, which capsized.
Beymer quotes a 'recent' letter by her daughter:
I do not remember very much about our imprisonment except that I used to cry myself to sleep from hunger. . . . There was a tiny closet in our room in which mother contrived to loosen a plank that she would lift up, and the prisoners of war underneath would catch hold of my legs and lower me into their room; they were allowed to receive fruit, etc., from the outside, and generously shared with me, also they would give mother news of the outside world. (On hazardous service pp.202-203).
- William Gilmore Beymore. On hazardous service: scouts and spies of the North and South. New York: Harper & Brothers, 1912. Pages 179-210 are about Rose Greenhow.
- Edwin C. Fishel. The secret war for the Union: the untold stories of military intelligence in the Civil War. Boston: Houghton Mifflin Company, 1996. Pages 57-70 and 575-578 deal with Rose Greenhow.
- Rose Greenhow. My imprisonment and the first year of abolition rule at Washington. London, 1863.
- Ishbel Ross. Rebel Rose: life of Rose O'Neal Greenhow. New York: Harper & Brothers, 1954. [I have not yet read this.]