The Italian sparrow is found in northern and central Italy, Corsica, and small parts of France, Switzerland, Austria, and Slovenia. Its distribution was described by Italian zoologist Enrico Hillyer Giglioli in 1881 as professing "'Conservative opinions'; for it keeps strictly within our current political frontiers". At the northernmost edge of its range in the southern Alps, there is a narrow hybrid zone about 20–30 km (12–20 mi) wide with the house sparrow. In southern Italy, there is a gradual clinal trend with the Spanish sparrow, with birds increasing in their similarity to the Spanish sparrow in appearance and ecology further south, from around Naples to western Sicily, where birds resemble pure Spanish sparrows. However, this trend may be superficial, and the "Handbook of the Birds of the World" recognises birds from Sicily and Crete as Italian sparrows.