Carex obnupta is a species of sedge known by the common name slough sedge. It is native to western North America from British Columbia to California where it grows abundantly in wet, often saline habitat such as wetlands. The plant produces upright, angled stems approaching 1.2 meters in maximum height, growing in beds or colonies from rhizome networks. The inflorescence is a cluster of flower spikes accompanied by a long leaflike bract. The pistillate spikes and sometimes the staminate spikes dangle on peduncles. The fruit is coated by a hard, tough, shiny perigynium which is generally dark in color.