Q: WHAT YEAR DID ATHALIAH’S REIGN END IN JUDAH?
A: IT DEPENDS WHAT CALENDAR YOU ARE USING!
On the Gregorian calendar (the one you might have on your wall) the year was 821 BC.
On the Hebrew calendar, sometimes called the biblical calendar, the year was 3226 AM.
2 Kings 11:3 - And he was with her hid in the house of the Lord six years. And Athaliah did reign over the land.