A spit or sandspit is a deposition bar or beach landform off coasts or lake shores. It develops in places where re-entrance occurs, such as at a cove's headlands, by the process of longshore drift by longshore currents. The drift occurs due to waves meeting the beach at an oblique angle, moving sediment down the beach in a zigzag pattern. This is complemented by longshore currents, which further transport sediment through the water alongside the beach. These currents are caused by the same waves that cause the drift.

The Curonian (Courish) Spit is a 98-kilometre (61 mi) long, thin, curved sand-dune spit that separates the Curonian Lagoon from the Baltic Sea. It is a UNESCO World Heritage Site shared by Lithuania and Russia. Its southern portion lies within Kaliningrad Oblast of Russia, and its northern within southwestern Klaipėda County of Lithuania.