In 1874, J. B. Mitchell was assigned to E Division with the rank of Staff Constable. Their assignment, along with Divisions A, B, C, D, and F was to bring law and order to western Canada. Divisions D, E and F were to travel to Manitoba to join with A, B and C Divisions. They traveled by train from Toronto to Fargo, North Dakota, U.S.A., as there were no train lines running through Canada yet. D, E and F Divisions traveled by horse from Fargo to Fort Dufferin (Emerson) where the Boundary Commission (engaged in establishing the Line between Canada and the U.S.A.) had an office. Here they met up with A, B and C Divisions and headed west. At La Roche Percée (near what is now Estevan, Saskatchewan) Colonel French sent A Division north to Edmonton to set up a post there. The rest of the Divisions continued westward.

By the time B, C, D, E and F Divisions had reached the foothills of Alberta, they were in poor condition. Great herds of bison moving east had stripped the land clean of grass. The horses and cattle of the Divisions had little to feed on and the horses were having difficulty adjusting to prairie grass as their food. The men had to walk beside their horses so their sick horses could make the journey. The bison stampedes had also tramped down water holes and small streams. Instead of water flowing, the men found stagnant sloughs. The men had to dip stones in vinegar and suck them for moisture. Water was scarce and their food supply was running dangerously low. On July 21, 1874, E Division, including J. B. Mitchell, went on strike