St. Helena
Sub-AVA · Napa County · District 4
27 CFR 9.149 · established 1995-09-11
Heat class III · 1991-2020 normals
Climate normals in three numbers
, Apr 1 – Oct 31
10 GridMET cells cover this region
raw 4 km GridMET would say IV
season rain, Apr 1 – Oct 31
48 mm of it in the , Sep 1 – Oct 31
Warm and cool vintages since 1980
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Rain across the season, and at harvest
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The boundary
Hovering a shaded region names it; a click opens its page.
Measured vineyard area
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Drought categories, year by year
Napa County — not St. Helena
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What's in the ground
6.3
pH, 1:1 water
16.8cm
, whole profile
155cm
to
Well drained
, dominant condition
Distribution across 41 · mean ◆, median │, p10–p90 bar
Dominant
- 22.4%
- 22.0%
- 16.8%
- 11.4%
- 5.9%
41 map units · soil described over 97.9% of the region’s area · 3.8% is water, rock outcrop or other non-soil · 37% of the described area has a restrictive layer within the profile.
Sand, silt and clay, against every other appellation
Loam
37% sand · 42% silt · 21% clay
Sandier than 28% of California appellations and clayier than 37%. Each grey point is one appellation’s topsoil; appellations nest, so this is a distribution of places rather than of land.
Plus 16% rock fragments by volume, which the triangle does not describe — the three fractions are of the fine-earth material only.
Elevation, slope and aspect
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Producers
A curated roster, not a census — only source-verified entries appear, 2772 published across the atlas.
Bearing acreage by variety
Napa County · District 4
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Price per ton
Napa County · District 4
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The appellation in federal law
The boundary, in the government’s own words (667 words)
(c) Boundary. The St. Helena viticultural area is located in Napa County in the State of California. The boundary is as follows: (1) Beginning on the Rutherford Quadrangle map at the point of intersection between State Highway 29 and a county road shown on the map as Zinfandel Avenue, known locally as Zinfandel Lane, the boundary proceeds in a southwest direction along Zinfandel Avenue to its intersection with the north fork of Bale Slough (blueline stream) near the 201 foot elevation marker; (2) Thence in a northwesterly direction approximately 2,750 feet along the north fork of Bale Slough to a point of intersection with a southwesterly straight line projection of a light duty road locally known as Inglewood Avenue; (3) Thence in a straight line in a southwesterly direction along this projected extension of Inglewood Avenue approximately 2,300 feet to its intersection with the 500 foot contour line in Section 7, Township 7 North (T7N), Range 5 West (R5W); (4) Thence along the 500 foot contour line in a generally northwesterly direction through Sections 7, 1 and 2, to its intersection of the western border of Section 2, T7N, R6W; (5) Thence northerly along the western border of Section 2 approximately 500 feet to its intersection with Sulphur Creek in Sulphur Canyon in the northwest corner of Section 2, T7N, R6W; (6) Thence along Sulphur Creek in an easterly direction approximately 350 feet to its intersection with the 400 foot contour line; (7) Thence along the 400 foot contour line in a generally easterly, then northwesterly, direction past the city of St. Helena (on the St. Helena Quadrangle map) to a point of intersection with a southwesterly straight line projection of the county road shown as Bale Lane in the Carne Humana Rancho on the Calistoga Quadrangle map; (8) Thence along the projected straight line extension of Bale Lane in a northeasterly direction approximately 700 feet to the intersection of State Highway 29 and Bale Lane and continuing northeasterly along Bale Lane to its intersection with the Silverado Trail; (9) Thence in a northwesterly direction along the Silverado Trail approximately 1,500 feet to an unmarked driveway on the north side of the Silverado Trail near the 275 foot elevation marker; (10) Thence approximately 300 feet northeasterly along the driveway to and beyond its point of intersection with another driveway and continuing in a straight line projection to the 400 foot contour line; (11) Thence in a northerly and then generally southeasterly direction along the 400 foot contour line through Sections 10 (projected), 11, 12, 13, 24 and 25 in T8N, R6W, Section 30 in T8N, R5W, Sections 25 and 24 in T8N, R6W, Sections 19 and 30 in T8N, R5W to a point of intersection with the city limits of St. Helena on the eastern boundary of Section 30 in T8N, R5W, on the St. Helena Quadrangle map; (12) Thence north, east and south along the city limits of St. Helena to the third point of intersection with the county road known as Howell Mountain Road in Section 29, T8N, R5W; (13) Thence in a northeasterly direction approximately 900 feet along Howell Mountain Road to its intersection with Conn Valley Road; (14) Thence northeasterly and then southeasterly along Conn Valley Road to its intersection with the eastern boundary of Section 28, T8N, R5W; (15) Thence south approximately 5,200 feet along the eastern boundary of Sections 28 and 33 to a point of intersection with the 380 foot contour line near the southeast corner of Section 33, T8N, R5W, on the Rutherford Quadrangle map; (16) Thence in a northwesterly direction along the 380 foot contour line in Section 33 to a point of intersection with a northeasterly straight line projection of Zinfandel Avenue; (17) Thence in a southwesterly direction approximately 950 feet along this straight line projection of Zinfandel Avenue to its intersection with the Silverado Trail; (18) Thence continuing along Zinfandel Avenue in a southwesterly direction to its intersection with State Highway 29, the point of beginning.