Cranberries are a group of evergreen dwarf shrubs or trailing vines in the genus Vaccinium subgenus Oxycoccus, or in some treatments, in the distinct genus Oxycoccus. They are found in acidic bogs throughout the cooler parts of the Northern Hemisphere.

Cranberries are low, creeping shrubs or vines up to 2 m long and 5 to 20 cm in height, with slender, wiry stems, not thickly woody, and small evergreen leaves. The flowers are dark pink, with very distinct reflexed petals, leaving the style and stamens fully exposed and pointing forward. They are pollinated by domestic honey bees. The fruit is a berry that is larger than the leaves of the plant; it is initially white, but turns a deep red when fully ripe. It is edible, with an acidic taste that can overwhelm its sweetness.

Cranberries are a major commercial crop in certain US states and Canadian provinces (see "Cultivation and Uses" below). Most cranberries are processed into products such as juice, sauce, and sweetened dried cranberries, with the remainder sold fresh to consumers. Cranberry sauce is widely regarded as an indispensable part of the traditional American and Canadian Thanksgiving menu.

Since the early 21st century in the United States, other such industrialized countries, and the global functional food industry, there has been a rapidly growing recognition of cranberries for their consumer product popularity, nutrient content and antioxidant qualities, giving them commercial status as a novel "superfruit".