The marionberry (Rubus L. subgenus Rubus) is a cultivar of blackberry released in 1956 by the USDA Agricultural Research Service breeding program in cooperation with Oregon State University. It is named after Marion County, Oregon, where the berry was bred and tested extensively in the mid-20th century.
A cross between the 'Chehalem' and 'Olallie' varieties, it is the most widely planted trailing blackberry in the world. Oregon accounts for over 90% of the worldwide acreage of marionberries.