Sentence:  The grant , which stretched southward to Lake Traverse - the headwaters of the <WSD>Red</WSD> - was made in May , 1811 , and by October of that year a small group of Scots was settling for the winter at York Factory on Hudson Bay . 
Meaning of the word marked with <WSD> tags:  a tributary of the Mississippi River that flows eastward from Texas along the southern boundary of Oklahoma and through Louisiana