The Pawnee called them " tirapihu ", meaning “ he buys or trades ”, as the Arapaho were the trading tribe in the Great Plains region.

They have long been closely linked with the Cheyenne tribe, who called them " Cloud Men ".
The name given to them by the Sioux has a similar meaning : " Blue Cloud Men ".

The Arapaho tribe historically living on the eastern plains of Colorado and Wyoming. They were allies of the Cheyenne tribe.

The Northern Arapahos live on the Wind River Reservation north of Lander Wyoming.

The Arapaho tribe most likely lived in Minnesota and North Dakota.
American expansion forced the Arapaho westward towards the area which is now Colorado, Wyoming, and Kansas.

When the U.S. was placing Indians on reservations, one group of the Arapaho were sent to Oklahoma.
There they shared the reservation with the Cheyenne and eventually the Cheyenne and Arapaho cultures grew similar.