Willamette Valley is an American Viticultural Area (AVA) which lies in the Willamette Valley of Oregon. The AVA is the wine growing region which encompasses the drainage basin of the Willamette River. It stretches from the Columbia River in the north to just south of Eugene in the south, where the Willamette Valley ends; and from the Oregon Coast Range in the west to the Cascade Mountains in the east. At 5360 sqmi, it is the largest AVA in the state, and contains most of the state's wineries; approximately 908 as of 2021. The AVA was established by the Bureau of Alcohol, Tobacco and Firearms (ATF), Treasury on January 3, 1984 after reviewing the petition submitted by Mr. David B. Adelsheim, Chairman, Appellation Committee, Oregon Winegrowers Association, and owner of Adelsheim Vineyards, proposing a viticultural area in northwest Oregon, as part of the Willamette River Basin, to be known as "Willamette Valley." Since then, ten distinctly featured areas, referred as "sub-AVA" or "sub-appellation", were recognized within the Willamette Valley AVA, with nine of them in the northern region and the Lower Long Tom AVA in the southern. The Willamette Valley has a cool, moist climate, and is recognized worldwide for its Pinot noir. Although not officially recognized, many wine connoisseurs further define the Willamette Valley into northern and southern regions with the demarcation being the latitude of Salem (approximately 45° north).

Climate

The climate of Willamette Valley is mild year-round. Winters are typically cool and wet, summers are dry and warm; heat above 90 °F only occurs 5 to 15 days per year, and the temperature drops below 0 °F once every 25 years. Most rainfall occurs in the late autumn, winter, and early spring, when temperatures are the coldest. The valley gets relatively little snow (5 in to 10 in) per year. The hardiness zone is mostly 8b. Not all portions of the Willamette Valley are suitable for vineyards, however, and the largest concentration of wineries is found west of the Willamette River, on the leeward slopes of the Coast Range, or among the numerous river and stream valleys created by Willamette River tributaries. By far, the largest concentration of wineries is in Yamhill County.

Sub-appellations

There are ten American Viticultural Areas within the Willamette Valley AVA. These smaller AVAs recognize regions within the larger Willamette Valley AVA that have distinctive climate, soil, elevation, or other physical features that make them noteworthy for wine production.

Chehalem Mountains AVA

The Chehalem Mountains AVA, established in 2006, stretches 20 mi from Wilsonville in the southeast to Forest Grove in the northwest. The Chehalem Mountains includes Ribbon Ridge, Parrett Mountain, and Bald Peak. The petition process for the creation of the AVA began in 2001 and was led by David Adelsheim of Adelsheim Vineyard. It contains two sub-regions, Laurelwood District AVA and Ribbon Ridge AVA.

Dundee Hills AVA

The Dundee Hills AVA in the hills north and west of Dundee. The area is 6940 acre in total size, with 1300 acre cultivated. Over 25 wineries and independent vineyards in this region produce over 44,000 cases of wine. The area is particularly noted for its Pinot noir; several wineries in the AVA have won international recognition for their wines.

Eola-Amity Hills AVA

The Eola-Amity Hills AVA stretches from the town of Amity in the north to Salem in the south. The hills cover an area west of the Willamette River approximately 15 mi long by 6 mi wide. The Eola-Amity Hills area benefits from steady winds off the Pacific Ocean that reach the Willamette Valley through the Van Duzer corridor, a gap in the Oregon Coast Range, moderating the summer temperatures. The name Eola is a tribute to the windy conditions in the area, and is derived from Aeolus, the Greek god of wind.

Laurelwood District AVA

The Laurelwood District AVA is located west of the city of Portland and lies entirely within the Willamette Valley and Chehalem Mountains AVAs since it was established by the TTB in May 2020. It covers approximately 33600 acres and contains 25 wineries and approximately 70 commercially-producing vineyards that cover a total of approximately 975 acres. The distinguishing feature of the Laurelwood District is the predominance of the Laurelwood soil series.

Lower Long Tom AVA

The Lower Long Tom AVA was established in 2021. It is located in the southern Willamette Valley in Lane and Benton Counties, near the towns of Junction City and Monroe. Its coverage is approximately 25000 acres and contains 12 wineries and 24 commercially-producing vineyards that plant approximately 575 acres. As of 2022, the Lower Long Tom is the only nested appellation located in the southern Willamette Valley AVA, in contrast to nine nested appellations in the north. The region is primarily known for its Pinot noir and Pinot gris.

McMinnville AVA

The McMinnville AVA near McMinnville was established in 2005, in the hills to the southwest of McMinnville, roughly running from McMinnville to Sheridan. The AVA includes 14 wineries and 523 acre of vineyards, and includes lands with elevations ranging from 200 to 1000 ft.

Ribbon Ridge AVA

The Ribbon Ridge AVA, between Newberg and Gaston, is a ridge containing uplift of ocean sediment. It lies at 45° 21' N, 123° 04' W, at the northwest end of the Chehalem Mountains. The name originates in the 19th century. The ridge is approximately 0.25 mi wide and 3.50 mi long, and is 3350 acre in area, with 500 acre planted on 20 vineyards. It is estimated that between 1000 acre and 1400 acre in the region is suitable for planting.

Tualatin Hills AVA

The Tualatin Hills AVA was established in May 2020 and is located in the upland hills of the Tualatin River watershed and encompasses elevations between 200 and 1000 ft. To the south and southeast are the Chehalem Mountains, which includes elevations of over 1000 ft, are considered to be a separate, distinct landform from the Tualatin Hills. The AVA is approximately 144000 acre with 33 commercially-producing vineyards covering approximately 860.5 acre and 21 wineries. The distinguishing features of Tualatin Hills are its soils, elevation and climate.

Van Duzer Corridor AVA

The Van Duzer Corridor AVA is located just west of the Eola-Amity Hills AVA covering approximately 59871 acre. The Van Duzer wind AVA is known low elevations and gently rolling hills, cool breezes from the Pacific Ocean, and soils which are primarily uplifted marine sedimentary loams and silts with alluvial overlay. The AVA was established in 2019.

Yamhill-Carlton District AVA

The Yamhill-Carlton District AVA is located in the area surrounding the towns of Yamhill and Carlton. Only grapes grown in vineyards with elevations ranging from 200 ft to 1000 ft may be used to produce wines that bear the appellation name on their labels. The AVA includes over 1200 acre of vineyard, and the region is in the rain shadow of the 3500 ft Oregon Coast Range, a short distance to the west. The AVA was established in 2005.