A drag-behind square hay bale accumulator that groups ten (10) bales of hay is claimed. The grouping configuration has the advantage of providing the first two bales of hay turned at right angles to the remaining bales, to provide for improved stacking of the hay bales. The accumulator is comprised of an open framework within which channels for routing the bales are positioned. After a group of ten (10) bales is collected, the accumulator leaves the bales on the field in a grouping that can be mechanically picked up and stacked.