There are 6 US Post Offices in Teton County serving a total of 20,261 residents equating to 3,377 residents per post office. It's estimated that approximately 32,339 packages are handled across the 6 county post offices annually. Teton County is a county located in the U.S. state of Wyoming. As of the 2010 census, the population was 21,294. Its county seat is Jackson. It is east from the Idaho state line. Teton County is part of the Jackson, WY-ID Micropolitan Statistical Area. Teton County contains the affluent Jackson Hole skiing area. In addition, the county contains all of Grand Teton National Park and 40.4% of Yellowstone National Park's total area, including over 96.6% of its water area (largely in Yellowstone Lake)."