HEADQUARTERS NORTHWESTERN INDIAN EXPEDITION,
Fort Berthold, August 29, 1864.

SIR: I started from Fort Union on the 21st and reached this point yesterday. Our march at first had to be slow on account of our animals, but after marching about seventy miles the grass improved greatly, point, as I would here, no doubt, be able to learn something about the Sioux from the Ree Indians. After marching down the river six days, about eighty miles by land below Union, we came to a place near the head of the Big Bend, where a very large body of Indians had crossed the Missouri, about ten days before, and camped there one night. There were very few trails of lodges, but a very large number of pony tracks, some thousand at least. Their track, after going north, appeared to turn to the east and cross the Little Knife River, in the direction of Devil's Lake. These were undoubtedly the same Indians whose trail I mentioned we crossed after our fighting in the hills east of the Yellowstone, and I had no doubt they were the Yanktonais; this I afterward found out was the case. They may have gone into the British possessions, for all the Indians well know we are not authorized to cross the line. The half breeds of the North keep them well posted in these matters; it is to their interest to draw all the trade to their country. On my arrival at Berthold I met all the Indians of the Ree, Gros Ventres, and Mandan Nations. They were busy collecting their corn, of which they have a very large amount. They were all glad to see me, as they expressed themselves. They now felt as if they were relieved from slavery. They offered their services to go out with me. A large party of them had started in July to meet me, but formed by my trail I had passed so long ago they went to Fort Rice. These Indians have for years been friends to the whites; they are industrious and look well off. The Sioux tried hard to get them to join them. This they would not do, but had to make peace with them, as they are too weak to contend against this powerful tribe. They ought to be protected, as they afford, in a measure, a barrier against the Sioux holding all the country near the river. On this account, and as I deemed it necessary to keep up the communication up the river, I ordered Captain Moreland, with his company (G, Sixth Iowa Cavalry), to garrison the fort. This post is the best point from which to supply a post at Devil's Lake.

In conversing with the Rees in regard to the trail I crossed, they all agreed that undoubtedly the Sioux had gone to the Maison du Chien Butte, and not to the line. The day after I arrived a Yanktonais Indian arrived, who had married a Ree squaw; he came to see me; I knew him as the brother of Big Head. He reported that he had just come from the camp of the Yanktonais, at a lake, the head of the Little Knife River; that there they had met a party of half-breeds of the North, who had furnished them seven kegs of powder and balls, and that by their invitation they were then on their way to the British line. He also stated that the Chiefs Black Catfish and Medicine Bull and some of the head men had told him that they wished to make peace, and wanted to come in, but were afraid; that they would not have got into this scrape had it not bee for the Unkpapas, and other tribes south; that at the first battle I had they were satisfied the Unkpapas were better at talking then fighting; that at the next fight they moved out of the way and then left the rest, going north, while the rest had gone into the Black Hills; also that Two Bears left togo to Fort Rice. The Indians had lost most of their lodges and baggage, and were in a very