The map functions as a kind of guidebook, with numerous notes and commentaries in Clark’s difficult handwriting. He provides directions to Santa Fe, shown here; to get there, it is “best to ascend the third fork to the mountains thence along the foot of said mountains to the pass.” In other places, Clark makes note of information he received from explorer Zebulon Pike about “innumerable herds of buffalo” and about a kind of grass “similar to our salt meadow grass from the great quantity of salt.” And like every tourist crossing the midsection of the country, he is careful to point out a spot where, according to Pike, “the mountains are first seen.”