Yuma Simpson (nee Hickman), was the mother of Abe and Homer's paternal grandmother, who was apparently from "The Old Country", which was most likely in Ireland, Scotland or Northwest England. Her name was revelead on The Simpsons Uncensored Family Album but it was never mentioned on the series.
Yuma Hickman was born in the Old Country (assuming Abe's story is to be trusted), to Willard Hickman and Theodora Hickman. Yuma married Orville Simpson in the early 1900s. They had at least twelve children, including Hubert, Tyrone, Cyrus, Abraham, Bill, Fester, Chet and Hortense. The family emigrated to the USA when Abraham was a young child, and for a few years, they lived inside the Statue of Liberty, along with their sons, until the head of it was filled with too much garbage. While in the US, she and Orville had Bill Simpson, who grew to become a Communist. Around the time of the Second World War, their son Chet, was born, and would grow to run an unsuccessful shrimp company. Later, the family would move to Springfield, USA, the town in which the show is set. Although Yuma's death has never been mentioned, she presumably died before her great-grandchildren Bart, Lisa or Maggie were born.
- Episode – "Much Apu About Nothing" (flashback)
- Episode – "Bobby, It's Cold Outside" (Mentioned in Flashback)
- Book – The Simpsons Uncensored Family Album
- Comic book – Abe's First Radio