Hickson is now recognised for her different perspective on Irish history as a financially insecure Protestant Unionist during a time when nationalism was the growing movement. She was friends with significant figures in the field including W.E.H. Lecky. Her work on the history of Ireland in 1641 created controversy about the veracity of testimonies about the violence of Irish Catholics against Protestant settlers. Though attempting to be as unbiased as possible she overestimated the number of Protestants killed significantly. Hickson was concerned by the lack of attention given to this interpretation. Her work was not aimed at appealing to the popular. The preface was written by James Anthony Froude. Transcriptions she made are currently in the London library of Society of Genealogists and the National Library of Ireland. She lived at "Hillville" in Cloghane, Co.Kerry. Her father built this on the site of an earlier house in 1833. Hickson died in Kingston College, Mitchelstown in 1899 and was brought home to be buried in Tralee.