The Louisiana Waterthrust is a small bird, usually about 5 inches in length. The bill is pointed. Look for a black eyeline beneath a brown cap. The upperparts are solid grayish-brown with a white unstreaked underpart. The legs are an odd pink color. Its preferred habitat is marshes and deep underbrush. Because of its small size, it is difficult to see it in its natural habitat.

This bird is more reminiscent of a wren than a warbler. But Wrens tend to carry their tails upright and have a very different shape. The worm-eating warbler has black and buff head stripes and a buff to white breast. Because of these similarieties, the Waterthrush is often mistaken for the more common Wren.