Her specimens, artwork and documents are in the most significant museum collections in the UK, Ireland and the USA. She bequeathed her collection of plant specimens to Dawson Turner and many are now in the Natural History Museum, London. Her drawings were given by her sister in law, Matilda, to Dawson Turner, and over two hundred of her drawings of seaweeds are now in the archives of the Royal Botanic Gardens, Kew, with some in store at Sheffield City Museum. Specimens and drawings that had been sent to leading botanists, and featured in their publications, went into their collections. These include collections at Trinity College, Dublin; the Linnean Society, London (Smith collection); and the New York Botanical Garden (William and Lynda Steere Herbarium). Her letters to Dawson Turner are in Trinity College, Cambridge; and Dawson Turner's letters to her are in Kew Botanical Gardens' library and archives. Kew also has letters from Mackay to Hutchins, and Trinity College Dublin has her letters to him.