Palustrine wetlands are a distinctive class of inland, nontidal wetlands characterized by the presence of standing or saturated water and vegetation adapted to hydric conditions. The term “palustrine,” derived from the Latin palus meaning “marsh,” refers to wetlands typically found in low-lying basins, floodplains, or depressions that experience seasonal, intermittent, or permanent flooding. Unlike coastal or riverine wetlands, palustrine systems are largely isolated from tidal influence and are defined by their unique hydrology, vegetation, and soil characteristics.

Palustrine wetlands include all nontidal areas dominated by trees, shrubs, persistent emergent plants, mosses, or lichens. Wetlands lacking such vegetation are also considered palustrine if they meet the following criteria: the area is less than 8 hectares (20 acres), there are no active wave-formed or bedrock shorelines, the water depth in the deepest part does not exceed 2 meters at low water, and the salinity from ocean-derived salts remains below 0.5 per thousand.1

Palustrine wetlands encompass a wide variety of ecological types, including marshes, wet prairies, fens, bogs, shrub wetlands, and forested wetlands. Each type is distinguished by its hydrological regime, soil composition, and plant community structure. Herbaceous-dominated marshes and wet prairies thrive in shallow, nutrient-rich waters, whereas bogs and fens accumulate peat and support mosses such as Sphagnum in nutrient-poor conditions. Shrub and forested wetlands provide complex woody vegetation, including willows, alders, and swamp forests, which are critical habitats for many birds, amphibians, and invertebrates.