Barn Swallows (Hirundo rustica) historically nested along cliffs, in caves, and in other natural situations. Currently, nearly all reported nests of this species are on walls and beams of bridges, buildings, and other human-derived structures. Both natural and man-made nest sites typically share one thing in common: a horizontal surface for nest attachment. We describe a Barn Swallow nest that was constructed on a branch overhanging a river in southeastern Oregon. This is the first documented occurrence of this behavior by Barn Swallows and we believe it to be the result of high competition for a limited number of suitable nest sites in the study area.