The wagon ruts of the Santa Fe Trail are visible looking east, up and over the bank of the ditch, with a characteristic difference in the color and texture of the grass in the ruts. Between Pawnee Rock and Santa Fe, New Mexico, wagons customarily traveled four abreast to allow quicker circling in case of attack. In the distance to the south, trees line the banks of the Arkansas River, which during the early years of the trail was the boundary between Mexico and the United States.