Complex sentence: The extreme eastern section of Oregon in the Snake River Valley, including Ontario, is part of the Treasure Valley, which extends east to Boise, Idaho; unlike the rest of the state, that section lies within the Mountain Time Zone.
Split into simpler sentences: The extreme eastern section of Oregon in the Snake River Valley, including the city of Ontario, is part of the Treasure Valley, which extends east to Boise, Idaho. Unlike the rest of the state, that section lies within the Mountain Time Zone.