Called "the Fair" for her golden hair, she was born March 25th, 1421 by Shire Reckoning (which would be Third Age 3021), which was at the same time the first day of the Fourth Age in Gondor. Elanor was also the only one of Samwise's children known to the Ringbearer, Frodo Baggins, and her name was a suggestion by him, a reference to the sun-star, a little golden flower blooming in the land of Lothlórien — his perfectly satisfied Sam's desire for a name that was both elvish and yet at the same time a simple flower-name as many hobbit-lasses had.
In 1436 Elanor became a maid of honor to Queen Arwen Evenstar, and in 1451 she married Fastred of Greenholm. Four years later Fastred was named Warden of Westmarch by the Thain at the request of Samwise. Elanor and her husband then moved to the Undertowers on the Tower Hills where their family (becoming known as the Fairbairns of the Towers) would live for many generations.
Besides her presence as an infant in the last chapter of the published Lord of the Rings, and the details noted in the appendices of that book, Elanor's most significant role was in the two versions of the written but unpublished epilogue of Lord of the Rings, later published in The History of Middle-earth volumes. In that epilogue we see Elanor talk with her father about the importance of the events that transpired in the story and also about the coming of King Aragorn and Queen Arwen for a visit. Elanor's affectionate name for her father is Sam-dad, while Sam calls her Elanorellë.