Clowta Simpson (née Stillman) was the daughter of Omar Stillman and Ettiwanda Trownse. Her husband was named Garwood Simpson. They had five children: Howland Simpson, Zeke Simpson, Hiram Simpson, Pippa Simpson and Floyd Simpson. She was the great-great-great-grandmother of Homer Simpson.
According to the season 21 episode, "The Color Yellow", Homer's great-great-great-grandmother was Mabel Simpson, and not Clowta Stillman. It is possible, however, that Clowta is the same person as Mabel, and the latter was taken out of the family tree to avoid controversy.