It is about 14 cm (5.5 in) long with ash-brown upperparts and paler underparts, and a short, square tail that has distinctive white patches on most of its feathers.

The Eurasian crag martin was formally described as Hirundo rupestris by Italian naturalist Giovanni Antonio Scopoli in 1769[2] and was moved to the new genus Ptyonoprogne by German ornithologist Heinrich Gustav Reichenbach in 1850.

[4] The genus name is derived from the Greek ptuon (πτύον), "a fan", referring to the shape of the opened tail, and Procne (Πρόκνη), a mythological girl who was turned into a swallow.

Two races, Central Asian P. r. centralasica and P. r. theresae in the Atlas Mountains of Morocco, have been proposed, but the slight differences in size and colour show no consistent geographical pattern.

[6] Fossils of this species have been found in Late Pleistocene deposits in Bulgaria,[7] and in central France in layers dated at 242,000 to 301,000 years ago.

This species can be distinguished from the sand martin by its larger size, the white patches on the tail, and its lack of a brown breast band.

Rapid wing beats are interspersed with flat-winged glides, and its long flexible primaries give it the agility to manoeuvre near cliff faces.

The vocalisations include short high pli, and piieh and tshir calls resembling those of the linnet and the house martin, respectively.

[17] The Eurasian crag martin breeds in mountains from Iberia and northwesternmost Africa through southern Europe, the Persian Gulf and the Himalayas to southwestern and northeastern China.

Northern populations are migratory, with European birds wintering in north Africa, Senegal, Ethiopia and the Nile Valley, and Asian breeders going to southern China, the Indian subcontinent and the Middle East.

[18] Some European birds stay north of the Mediterranean, and, like martins in warmer areas such as India, Turkey and Cyprus, just move to lower ground after breeding.

[6] The Eurasian crag martin's choice of nest sites is very similar to that of Savi's pipistrelle, Hypsugo savii; the bird and the bat often breed in the same locations and have almost identical ranges in Europe.

[24][25] In South Asia, migrant Eurasian birds sometimes join with flocks of the dusky crag martin and roost communally on ledges of cliffs or buildings.

The nest, built by both adults, is an open half cup made of mud and lined with soft material such as feathers or dry grass.

[30] An Italian study showed that, as with other aerial feeders, the start of breeding was delayed by cold or wet weather, but this had no influence on the clutch size nor on the number of fledged young.

[29] The Eurasian crag martin feeds mainly on insects caught in its beak in flight, although it will occasionally take prey items off rocks, the ground, or a water surface.

The crag martin exploits the area close to the cliff when it hunts, relying on its high manoeuvrability and ability to perform tight turns.

[27] This species is occasionally hunted by the peregrine falcon, which shares its mountain habitat,[31] and during its migration over the Himalayas, it is reported to be subject to predation by crows.

With its very large range and high numbers, the Eurasian crag martin is not considered to be threatened, and it is classed as Least Concern on the IUCN Red List.