American Viticultural Areas (AVAs)
AVAs are Federally-designated wine grape growing regions with specific geographic or climatic features that distinguish them from surrounding regions and influence the wine produced there. Each AVA has clearly defined boundaries that are based on natural features such as rivers, mountains, valleys, or climate zones. Boundaries are often determined by unique soil types, microclimates, and elevation.
AVAs highlight the distinct terroir of a specific region. The term “terroir” refers to the environmental factors that influence the flavor and quality of wine, including soil, climate, and topography. These different conditions can have both subtle and profound influences on the character of the wine.
The greater Willamette Valley AVA, established in 1984, spans approximately 5,360 square miles, encompassing the drainage basin of the Willamette River. It extends from the Columbia River near Portland, through Salem, to the Calapooya Mountains near Eugene, and is bordered by the Coast Range to the west and the Cascade Mountains to the east. The valley floor is characterized by fertile alluvial soils, while the hillsides feature a dynamic mix of porous volcanic soils, loess-derived sand, silt, clay, and ancient sedimentary layers, all contributing to the region’s exceptional viticultural diversity.
Within this expansive AVA are eleven sub-AVAs, each recognized for its distinctly unique terroir. Excalibur serves nine of these sub-AVAs, offering our clients a comprehensive perspective on the Willamette Valley’s most celebrated wine regions.
Let us know if you find one (or more) of these AVAs especially exciting.
Excalibur Serves These Nine AVAs
Click on any map for a larger version.
(Established 2020)
LOCATION: The large Tualatin Hills AVA spans 144,000 acres in the northwestern corner of the Willamette Valley, approximately 20 miles west of Portland, encompassing the upland hills of the Tualatin River watershed., bordered to the south and southeast by the Chehalem Mountains.
CLIMATE: The region enjoys the rain shadow of the Coast Range, resulting in slightly lower rainfall, cooler spring temperatures, and more temperate, drier conditions during the critical fall harvest period.
SOIL: The AVA features the largest concentration of Laurelwood soils in Oregon, consisting of well-drained windblown volcanic silt, known as loess, deposited over basalt bedrock during the Missoula Floods approximately 12,000 years ago. The fine, silty texture of Laurelwood soils offers excellent drainage and moderate fertility, fostering deep root development in grapevines.
TOPOGRAPHY: The AVA aligns with the Tualatin River watershed, with elevation ranging from 200 to 1,000 feet.
VARITIES GROWN: Chardonnay, Gewürztraminer, Riesling, Pinot Gris, Pinot Noir, Sauvignon Blanc
LOCATION: The Laurelwood District AVA is 25 miles southwest of Portland, encompassing over 33,000 acres. It lies entirely within the Chehalem Mountains AVA, covering the northern slopes and includes the towns of Cornelius, Scholls, and Sherwood.
CLIMATE: The AVA enjoys a temperate climate with warm, dry summers and cool, wet winters. Typically, summers temperatures only rise above 90°F (32°C) on 5 to 15 days per year, while winters are cool and damp. Most rainfall occurs during late fall, early winter, and early spring, providing a favorable environment for viticulture.
SOIL: Unique Laurelwood soils, which consist of a 15-million-year-old basalt base overlain by loess — a fine, windblown silt — deposited over the past 200,000 years. Soil composition varies in depth from 4 feet to mere inches, depending on elevation, and contributes to the distinct terroir of the region’s wines.
TOPOGRAPHY: Characterized by the north- and east-facing slopes of the Chehalem Mountains, with vineyards situated between 200 and 1500 feet, providing diverse microclimates ideal for viticulture.
VARITIES GROWN: Chardonnay, Gewürztraminer, Muscat, Pinot Gris, Pinot Noir, Riesling
(Established 2006)
LOCATION: The Chehalem Mountains AVA spans over 62,000 acres across Yamhill, Washington, and Clackamas counties and includes the Laurelwood District and Ribbon Ridge AVAs. Located approximately 19 miles southwest of Portland, this region features diverse terrain, including several distinct spurs, mountains, and ridges.
CLIMATE: Elevation ranging from 200 to 1,633 feet leads to significant climatic variations. Annual precipitation varies from 37 inches at lower elevations to 60 inches at higher points. This diverse topography results in the greatest temperature fluctuations within the Willamette Valley, causing up to a three-week difference in the ripening period of Pinot Noir grapes.
SOIL: The Chehalem Mountains AVA is distinguished by its convergence of three primary soil types: ancient marine sedimentary soils from uplifted seabeds, iron-rich red soils derived from Columbia River basalt lava flows, and younger loess soils formed from windblown glacial silt. This unique combination within a single region contributes to the complexity and diversity of its wines.
TOPOGRAPHY: The AVA comprises a series of hilltops, ridges, and spurs uplifted from the valley floor. This appellation encompasses all land in the area above 200 feet in elevation up to 1,633 feet (Bald Peak).
VARITIES GROWN: Chardonnay, Gamay Noir, Gewürztraminer, Marechal Foch, Pinot Blanc, Pinot Gris, Pinot Noir, Riesling, Syrah.
LOCATION: At 3,350 acres, the Ribbon Ridge AVA is the smallest in Oregon, located approximately 22 miles southwest of Portland, four miles northwest of Dundee, nestled between the towns of Newberg and Gaston. It is contained entirely within the Chehalem Mountains AVA. The ridge is defined by local geographic boundaries and an uplift of ocean sediment, contributing to its unique terroir.
CLIMATE: Protected by geographical features to the north, south, and west, Ribbon Ridge’s grape-growing hillsides experience a slightly warmer and drier climate compared to adjacent valley floors. This moderate climate fosters early spring growth, consistent ripening during summer, and a prolonged maturation period in the fall, ideal for cultivating high-quality wine grapes.
SOIL: Ribbon Ridge is characterized by predominantly marine sedimentary soils, specifically the Willakenzie series, which are younger, finer, and more uniform than the alluvial sedimentary and volcanic soils of neighboring regions. These moderately deep, well-drained silty clay-loam soils are of low fertility, creating optimal conditions for cultivating high-quality grape varieties such as Pinot Noir.
TOPOGRAPHY: Ribbon Ridge is a distinct landform extending approximately 3.5 miles in length and 1.75 miles in width from the Chehalem Mountains. Rising about 683 feet above the Chehalem Valley floor, it presents an island-like appearance, setting it apart from the surrounding terrain.
VARITIES GROWN: Cabernet Sauvignon, Chardonnay, Gamay Noir, Gewürztraminer, Pinot Gris, Pinot Noir, Riesling, Sauvignon Blanc
LOCATION: The Dundee Hills AVA is located 28 miles southwest of Portland. This region encompasses about 6,940 acres, forming a distinctive north-south oriented landmass that rises above the surrounding Willamette and Chehalem Valleys.
CLIMATE: The Dundee Hills AVA benefits from natural geographic protections that moderate its climate. The Coast Range to the west diminishes the impact of Pacific Ocean rainfall and windstorms, creating a rain shadow effect that results in annual precipitation of 30 to 45 inches, primarily during the winter months outside the growing season. Additionally, the elevation and slope of the Dundee Hills provide vineyards with warmer nights and reduced occurrences of frost and fog compared to the surrounding valley floors, fostering favorable conditions for viticulture.
SOIL: The Dundee Hills AVA is renowned for its rich, red volcanic Jory soils, formed from ancient basalt flows over 14 million years ago. These soils, composed of silt, clay, and loam, typically reach depths of 4 to 6 feet, providing excellent drainage and low fertility, which are ideal conditions for cultivating high-quality wine grapes like Pinot Noir.
TOPOGRAPHY: A single, continuous landmass that rises above the surrounding valley floors, with elevations ranging from 200 feet to 1,067 feet. The terrain features a north-south oriented spine with ridges and small valleys extending to the east, south, and west, creating a diverse landscape influencing vineyard microclimates.
VARITIES GROWN: Chardonnay, Pinot Blanc, Pinot Gris, Pinot Noir, Riesling
(Established 2004)
LOCATION: The Yamhill-Carlton AVA is situated 35 miles southwest of Portland and encompasses the towns of Yamhill and Carlton within its 60,000 acres.
CLIMATE: The Coast Range to the west rises majestically to nearly 3,500 feet, creating a natural “rain shadow” that shelters the AVA. Further protection comes from Chehalem Mountain to the north and the Dundee Hills to the east. These moderate growing conditions provide an ideal environment for cultivating cool-climate grape varieties.
SOILS: Characterized by coarse-grained, ancient marine sedimentary soils layered over sandstone and siltstone. These well-draining soils are perfectly suited for viticulture, allowing vines to thrive. Grapes cultivated in this unique soil type often produce wines with lower acidity compared to those grown in basaltic or wind-blown soils, contributing to the region’s distinctive wine profile.
TOPOGRAPHY: Gentle ridges encircle the towns of Yamhill and Carlton in a distinctive horseshoe shape, with the meandering North Yamhill River flowing through the heart of the region. Vineyards flourish on slopes positioned at elevations between 200 and 1,000 feet, avoiding the frost-prone valley floors and the cooler temperatures of higher altitudes which are less friendly to ripening.
VARITIES GROWN: Chardonnay, Dolcetto, Gamay Noir, Gewürztraminer, Melon, Muscat, Muscat Ottonel, Pinot Blanc, Pinot Gris, Pinot Meunier, Pinot Noir, Riesling.
LOCATION: The Eola-Amity Hills AVA is located 47 miles southwest of Portland, encompassing about 39,000 acres.
CLIMATE: Temperate with warm summers and mild winters, averaging about 40 inches of annual rainfall, mostly outside the growing season. Located east of the Van Duzer Corridor — a gap in the Coast Range — it receives cool Pacific Ocean winds that lower temperatures, especially on late summer afternoons. This preserves grape acidity by ensuring cool nights essential for optimal ripening.
SOIL: The soils are primarily composed of volcanic basalt from ancient lava flows, marine sedimentary rocks, and alluvial deposits at lower elevations. This combination creates shallow, rocky, well-drained soils that yield grapes with exceptional concentration.
TOPOGRAPHY: The Eola Hills and their northern extension, the Amity Hills, form a chain in the North Willamette Valley, shaped by volcanic activity and the collision of the Pacific and North American plates. The main ridge runs north-south, with numerous lateral ridges extending east-west. Most vineyards in the region are situated at elevations between 250 and 700 feet.
VARITIES GROWN: Auxerrois, Chardonnay, Gamay Noir, Grüner Veltliner, Gewürztraminer, Pinot Blanc, Pinot Gris, Pinot Noir, Riesling, Sauvignon Blanc, Syrah, Tempranillo, Viognier.
LOCATION: The Van Duzer Corridor AVA is 50 miles (80 km) southwest of Portland. This 60,000 acre AVA is named after the Van Duzer Corridor, a natural gap in the Coast Range that allows cool marine breezes to flow eastward into the Willamette Valley.
CLIMATE: Temperate, characterized by consistent high wind speeds, contributing to thicker grape skins and elevated levels of phenolic compounds in the fruit. The cooler temperatures result in slower fruit ripening, extending hang time and leading to reduced acidity levels in the grapes.
SOIL: Primarily composed of uplifted marine sedimentary loams and silts, with some areas featuring basalt over siltstone bedrock. These shallow, well-drained soils are rich in silt and clay, which help maintain a stable pH level, benefiting vine health and grape quality.
TOPOGRAPHY: Characterized by low elevations and gently rolling hills, facilitating the unobstructed flow of cool marine breezes from the Pacific Ocean through the Oregon Coast Range. The Van Duzer wind corridor creates a unique microclimate within the AVA.
VARITIES GROWN: Chardonnay, Pinot Blanc, Pinot Gris, Pinot Noir, Riesling, Sauvignon Blanc, Viognier
LOCATION: At nearly 60,000 acres, the McMinnville AVA lies just west of McMinnville, about 40 miles southwest of Portland, extending 20 miles south-southwest toward the Van Duzer Corridor.
CLIMATE: McMinnville’s east- and south-facing vineyards benefit from a Coast Range rain shadow, receiving only 33 inches of average annual rainfall — less than nearby regions like the Eola-Amity Hills. The foothills shield these vineyards from cold winds in spring and fall. Southern exposures mean these grapes enjoy drying winds from the Van Duzer Corridor, hindering mold and mildew during Oregon’s humid summers.
SOIL: Among Oregon’s oldest and most complex, featuring uplifted marine sedimentary loams and silts with alluvial overlays atop a basaltic base. Clay and silt loams average 20 to 40 inches in depth before reaching harder rock and compressed sediments interspersed with basalt pebbles and stones. This soil profile fosters vine stress, leading to grapes with concentrated flavors.
TOPOGRAPHY: Elevation ranges from approximately 82 to 833 feet, averaging around 164 feet. The area encompasses the east and southeast slopes of the Coast Range foothills, featuring silt loam soils with low to moderate permeability.
VARITIES GROWN: Pinot Blanc, Pinot Gris, Pinot Noir, Riesling, Syrah
Maps Courtesy of The Oregon Wine Board.