Washington State and Oregon may be neighbors, but their wine regions look very different. Oregon's vineyards lie west of the Cascades, on the coastal side of the Pacific Ocean. The climate can be described as maritime. In Washington, most of the vineyards are located on the eastern side of the mountains, where the climate is continental (hot, dry summers and cold winters). Washington's vineyards on the arid eastern plain benefit from irrigation, and all the Bordeaux varieties, as well as Chardonnay and Syrah are grown here. Merlot, in particular, has found notable success in Washington State. Although there are a few wineries around Puget Sound and the Seattle area, most source their grapes from the major viticultural areas to the east.

Columbia Valley: This is the largest region in terms of acres, and represents over half of Washington's vinifera varieties. Most vineyards across the state source their grapes from this area.

Yakima Valley: This is the second largest region in acres, but more wineries are located here than in the Columbia Valley

Walla Walla Valley: A tiny but fast-growing region in the southeast corner of the state, many of the top-quality wineries are here.