In 1805 the governor of the Louisiana Territory sent Lt. Zebulon Pike, without the permission of the federal government, to identify possible sites for new military posts in the Upper Mississippi region.  On September 23rd Pike met with a group 

of representatives from local Dakota villages at the confluence of the Minnesota and Mississippi Rivers. Pike presented a treaty that granted the United States two nine-square-mile tracts of land for the purpose of establishing military posts, 
one at the mouth of the St. Croix River and one at the mouth of the Minnesota River.  

This treaty had many problems.  First, only two of the seven Dakota leaders signed the treaty.  Second, the compensation for the land grant was also unspecified at the signing.  Without the input of Pike or any Dakota representatives, Congress later decided on the amount of $2,000, 1/100th of what Pike estimated as the value.  Although Congress ratified the treaty in April 1808, no payment reached the Dakota until 1819, when the Secretary of War decided to begin the construction of a fort on the site.  Third, the treaty was never proclaimed by the U.S. President. However, the biggest problem stemmed from the treaty's differently interpreted meanings.  How the Dakota understood the “grant” of this land is unknown.  Furthermore, because the Dakota retained the right to “pass, repass, hunt or make other uses of the said districts as they have previously done,” it is unlikely that they thought of this “grant” as a forfeiture of the ownership of the land.  Although later treaties between the U.S. and the Dakota made the cession of the land explicit, those treaties were only possible because of the fort, which was constructed on the basis of Pike’s Treaty.  The U.S retains ownership of the land at the confluence of the Minnesota and Mississippi Rivers, essentially without ever receiving the consent of the Dakota.