Most widely distributed terrestrial snake

The largest naturally occurring range for a land-based snake is that of the northern adder, or European adder (Vipera berus). Its east-to-west range across Eurasia is some 8,000 kilometres (5,000 miles) from the UK to Sakhalin Island off eastern Russia. These venomous snakes live as far north as Scandinavia and Russia's Kola Peninsula, 200 kilometres (125 miles) north of the Arctic Circle, to as far south as the Balkans region of the Mediterranean.

European adders live in a diverse range of habitats, including woodland, grassland, heath and moorland, farmland, and wetland areas. In terms of elevation, it occurs at sea level up to 2,600 metres (8,530 feet) in its more southern range.

If allowing for human-introduced species, then the most widely distributed terrestrial snake is the Brahminy blindsnake (Indotyphlops braminus), which although originally native to India is today found on all continents except Antarctica – including many islands. Its small size (adults are 150–180 millimetres/6–7 inches long) and habit of living among the root balls of plants have seen it transported all around the world with the translocation of exotic plants and crops, earning it the nickname of flowerpot snake.