The Walla Walla onion is named for Walla Walla county in Washington where it is grown. Its development began over a century ago when Peter Pieri, a French soldier who settled in the area, brought a sweet onion seed from the island of Corsica with him to the Walla Walla Valley. This sweet onion was developed by selecting and reseeding onions from each year's crop that possessed sweetness, jumbo size, and round shape.