牛奶蛇有25个亚种，每个亚种的外形相差很大，有的分类学家主张将其分为几个不同的种。 原产于美洲，分布范围从北美洲的加拿大南部一直到南美洲北部的厄瓜多尔尔和委内瑞拉一带。 成年蛇有60厘米左右长。

牛奶蛇表面光滑，体表颜色为三色交替环状，橘红、黑色和黄色，或橘红、黑色、白色交替，也有的品种不是环状，而是有红色大斑点。有的外形类似于剧毒的珊瑚蛇，这种警戒拟态是为了吓退天敌；但东部的牛奶蛇品种（L. t. triangulum）拟态则类似响尾蛇，有一种黑化变种几乎全为黑色 。

牛奶蛇一般生长在森林地带，也有部分品种可以生活在草原地带，通常栖息带岩石坡面上。

Lampropeltis triangulum, commonly known as a milk snake or milksnake, (French: Couleuvre tachetée; Spanish: Culebra-real coralillo) is a species of king snake. There are 24 subspecies of milk snakes. Lampropeltis elapsoides, the scarlet kingsnake, was formerly classified as the subspecies L. t. elapsoides, but is now recognized as a distinct species. The subspecies have strikingly different appearances, and many of them have their own common names. Some authorities suggest that this species may be split into several separate species. They are not venomous (or otherwise dangerous to humans).