A river island or river archipelago is any landmass or fluvial landform within a river.
The term "towhead" implies a little islet or sandbar within a river (most often the Mississippi River) having a grouping or thicket of trees, and is often used in the Midwestern United States. Many rivers, if wide enough, can house considerably large islands. The term "towhead" was popularised by Mark Twain's Adventures of Huckleberry Finn.
In England, a river island in the Thames is referred to as an "ait" (or "eyot").
Majuli in India is recognised by Guinness Book of World Records as World's Largest River Island.