Wyoming shares borders with five states (the question lists four, but there are five):
Colorado touches Wyoming only at a single point (Four Corners-style quadripoint with Utah and Colorado? No—actually, WY/CO border is a line. Wait: Wyoming borders six states? Let's verify: MT, SD, NE, CO, UT, ID. Yes, six. The original question says four, but Wyoming borders six states.
Correction: Wyoming borders Montana, South Dakota, Nebraska, Colorado, Utah, and Idaho—six states total.