If you didn't drive to Wyoming, rent a car once you arrive. The airports have major car-rental agencies, which offer four-wheel-drive vehicles and ski racks.
Northwest Wyoming is well away from the interstates, so drivers make their way here on two-lane highways that are long on miles and scenery. To get to Jackson from I–80, take U.S. 191/189 north from Rock Springs for about 177 miles. From I–90, drive west from Sheridan on U.S. 14 or Alternate U.S. 14 to Cody. U.S. 14 continues west to Yellowstone National Park, and in summer, you can also hook up with U.S. 191, which leads south to Jackson. Yellowstone National Park is closed to cars in winter.
Be extremely cautious when driving in winter; game crossings, whiteouts, and ice on the roads are not uncommon. Contact the Wyoming Department of Transportation for road and travel reports. For emergency situations, dial 911 or contact the Wyoming Highway Patrol.
Grand Teton Park Road Conditions. 307/739–3682; www.wyoroad.info.