The marsh terns are typically found in freshwater marshes, rather than coastal locations.
There are four species:
- Black Tern, Chlidonias niger
- White-winged Tern or White-winged Black Tern, Chlidonias leucopterus
- Whiskered Tern, Chlidonias hybridus
- The Black-fronted Tern, Chlidonias albostriatus (formerly Sterna albostriata) is now also recognized to belong to this genus (Bridge et al., 2005).