Riparia is a genus of passerine birds in the swallow family Hirundinidae. These are small or medium-sized swallows, ranging from 11 to 17 cm (4.3 to 6.7 in) in length. They are brown above and mainly white below, and all have a dark breast band. They are closely associated with water. They nest in tunnels which are usually excavated by the birds themselves in a natural sand bank or earth mound. They lay white eggs, which are incubated by both parents, in a nest of straw, grass, and feathers in a chamber at the end of the burrow. Some species breed colonially.