Her name could indicate that she was from Far Madding, given that -in is a common ending of names in Far Madding of both first names and surnames; as common are long surnames.
She was born in FY 738 and was elected Amyrlin from the Red Ajah in FY 939, the same year as Guaire Amalasan declared himself as the Dragon Reborn and Bonwhin ruled for more than fifty years, one of the longest reigns in the history of the White Tower.
For such catastrophe Bonwhin was removed from power in FY 992 and replaced with Deane Aryman from the Blue Ajah, who had uncovered damning evidence of Bonwhin's failures and mistakes. She was the last Amyrlin to be raised from the Red before Elaida a'Roihan.
Before Siuan Sanche, Tetsuan and later Bonwhin were the only Amyrlins to ever be officially stripped of stole and staff. Both of them had been Reds, and it was Bonwhin's replacement by a Blue that reignited the feud between the two Ajahs, culminating a thousand years later with the illegal deposition of Siuan Sanche.
After being deposed and stilled Bonwhin was kept as a scullion till she died, four years later at the age of 258.