Kogin Niobrara kogi ne da ke ratsa yankin Great Plains na arewacin Amurka, musamman ta jihohin Wyoming, South Dakota, da Nebraska. Yankin Kogin Missouri ne kuma yana da nisan mil 568 (kilomita 914). Sunan "Niobrara" ya samo asali ne daga kalmar 'yan asalin ƙasar Amirka wanda ke nufin "ruwa wanda ba shi da zurfi a kan duwatsu masu santsi."
