A century ago, the dwarf wedgemussel lived in at least 70 locations in 15 major watersheds along the Atlantic, from New Brunswick to North Carolina. Now, this small mussel is extirpated from Canada and found in only nine American watersheds.

Dwarf wedgemussels continue to live in small freshwater streams and medium-sized rivers in the eastern United States. They prefer bodies of water that have slow to moderate currents, with underlying sand, fine sediment or gravel substrates and streamside vegetation. Waters clouded with suspended silt are inhabitable for dwarf wedgemussels.

A typical dwarf wedgemussel is less than 5.5 centimetres long. Like all mussels, it has two hinged shells enclosing a soft inside. Its brown shell is oblong circular and may include yellowish-brown hues. The inside of its shell ranges from bluish to silvery-white, with an iridescent sheen in the back section. It is easy to overlook, as it tends to be half-buried in the river-bottom.