Stags Leap District Vineyards: River and Contour Lines, Hillside Rules, Permits and Water

By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.

The Stags Leap District is a compact Napa Valley appellation on the eastern side of the valley north of the city of Napa, bounded by the Napa River on the west, the Yountville Cross Road on the north and the 400-foot contour of the eastern hills. The Silverado Trail runs through it. Because the district is small and its edges are a river channel and an elevation line, owning land here comes down to exactly where a parcel sits relative to those lines, what the slopes under the hills allow, and what a winery on the Silverado Trail can be permitted to do.

Stags Leap District at a glance

Where the appellation runs

The boundary at 27 CFR 9.117 is short and drawn on a single USGS map. It begins where an intermittent drainage creek meets the Silverado Trail at the 60-foot contour, about seven miles north of Napa. From there a straight line of about 900 feet reaches the main channel of the Napa River, and the boundary follows the river’s main branch north. The rule specifically uses the main channel and not the southern branch near the levee, a detail that matters for parcels with land between the two. At the Yountville Cross Road the line turns northeast to the Silverado Trail, follows the Trail north about 590 feet to a gully, climbs that gully about 800 feet to the 400-foot contour, and then follows the contour generally southeast before descending an intermittent stream back to the start.

The rule states that the district lies within the Napa Valley AVA, established in 1981. TTB’s most recent change to the section, T.D. TTB-196 in November 2024, was part of a technical corrections rule rather than a boundary expansion. For how the district sits among its neighbors, see the Napa Valley appellation overview, the Oak Knoll District vineyard map post and our comparison of Rutherford and Stags Leap valley-floor vineyards.

Why the 400-foot line matters

On the east side, a single ranch can run from valley-floor blocks up into the hills. Everything below the 400-foot contour (and inside the other lines) is in the district; blocks above it are not, even on the same parcel. Before you value a hillside vineyard here, have the blocks plotted against the contour on the approved Yountville map.

Hillside edges: Napa County erosion control rules

The district’s eastern side climbs from the valley floor toward the hills, and that slope is where county rules start to apply. Under Napa County’s Conservation Regulations (Chapter 18.108), an erosion control plan is required for agricultural grading on slopes over 5%, including vineyard replanting on those slopes. New hillside planting plans are reviewed by the county and subject to CEQA. For replants, a Track II plan prepared by a consultant on the county’s pre-qualified list is approved ministerially, while Track I plans can be prepared by anyone and usually qualify for a categorical exemption if they meet its criteria. The county also notes extra rules in sensitive domestic water supply watersheds; ask the county whether any part of the parcel falls in one. See our vineyard development and environmental constraints guides.

Hillside parcels often carry the Agriculture, Watershed and Open Space designation in Napa’s General Plan, with a 160-acre minimum parcel size, while Agricultural Resource land on the valley floor has a 40-acre minimum. Measure J (1990) and Measure P (2008) require voter approval to redesignate that land, and the General Plan says the policies from those measures cannot be changed without a vote until after December 31, 2058. Confirm which designation and zoning (AP or AW) applies to each parcel; our Napa AP and AW zoning guide explains the difference.

Winery permits along the Silverado Trail

Wineries in the district operate under Napa County use permits, and the Winery Definition Ordinance in the General Plan (AG/LU-13) requires at least 75% Napa County grapes for wineries approved after 1990, with tours and tastings by appointment only. Those rules come into sharper focus for a site with access off the Silverado Trail. The county’s winery use permit application asks for trip generation for existing and proposed conditions and notes that projects under 110 new daily trips may avoid a full traffic study, although the Public Works Director can still require road improvements or a sight distance analysis. Winery coverage is capped at the lesser of 25% of the parcel or 15 acres, and accessory uses at 40% of the production area. A Water Availability Analysis, septic and process wastewater reports, and compliance with the county’s road and street standards are standard parts of the file.

Smaller changes can go through an administrative permit: interior remodels, shade structures up to 2,500 square feet, and building additions of up to 10% (capped at 2,500 square feet), as long as the accessory-to-production ratio stays in line. For a buyer of an existing Stags Leap winery, the permit’s production gallons, visitor and event limits, and hours are what you are really buying alongside the land. See our Napa winery use permit guide, Winery Definition Ordinance guide and winery due diligence checklist.

Water and the Napa River edge

The valley-floor portion of the district overlies the Napa Valley Subbasin, managed by the Napa County Groundwater Sustainability Agency under a plan DWR approved on January 26, 2023. The agency adopted groundwater sustainability fees in December 2025 (Resolution 2025-05) for subbasin properties outside the municipal service districts of Calistoga, St. Helena, Napa and Yountville; ask the seller for the parcel’s current bill. Wells and discretionary projects follow the county’s well permit standards and Water Availability Analysis requirements, last updated January 2024. Hillside wells above the valley floor can behave very differently from those on the alluvium, so ask for dry-season pump tests. See Napa groundwater rules and vineyard water rights.

On the west, the river itself is the boundary. Napa County’s Oakville to Oak Knoll restoration project covers about nine miles of the Napa River from Oakville Cross Road to Oak Knoll Avenue, a stretch that appears to include the district’s river edge, since the Yountville Cross Road crossing lies between those two points. It is funded by Measure A and state and federal grants and includes management of invasive and Pierce’s disease host plants. For riverfront parcels, ask what restoration work touches the property, what is recorded on title, and what the FEMA flood maps show for any building site; the county’s winery application also requires a hydrology analysis for projects in a floodplain or floodway.

Fire hazard and insurance

The eastern hills above the district are mapped under the state’s Fire Hazard Severity Zone program, which rates land Moderate, High or Very High. State Responsibility Area maps took effect April 1, 2024, and local-area maps were released in phases in early 2025. The Fire Marshal describes them as hazard maps rather than risk scores and notes they do not set insurance rates. Check the zone for every structure, including those near the 400-foot line, and get quotes early. See vineyard and winery insurance and wildfire smoke taint.

A due diligence list for a Stags Leap District vineyard

Work through these along with our full vineyard due diligence guide:

• Plot blocks against the 400-foot contour and the Napa River main channel in 27 CFR 9.117.
• For parcels with land between the river’s main channel and its southern branch, confirm which side each block falls on.
• Confirm General Plan designation, zoning (AP or AW) and legal lot status.
• Identify blocks over 5% slope that would need an erosion control plan to replant or extend.
• Ask whether any part of the parcel is in a sensitive domestic water supply watershed.
• For a winery, get the use permit, every modification, trip limits and compliance history.
• Check Silverado Trail access, sight distance and any road improvement conditions.
• Pull well logs, pump tests, any Water Availability Analysis and the current subbasin fee.
• For riverfront land, check FEMA flood zones and any restoration-related agreements.
• Review septic and process wastewater capacity; see winery wastewater.
• Check fire hazard zones and insurance availability for each structure.

Questions people ask

Sources & notes

1. eCFR: 27 CFR 9.117, Stags Leap District
2. eCFR: 27 CFR 9.23, Napa Valley
3. Napa County: Erosion Control Plan Review & Approval Process
4. Napa County: General Plan, Agricultural Preservation and Land Use Element
5. Napa County: Use Permit / Administrative Permit Application, Winery Uses
6. Napa County: Groundwater Sustainability
7. Napa County: Habitat Restoration & Monitoring (Oakville to Oak Knoll)
8. Office of the State Fire Marshal: Fire Hazard Severity Zones

General information, not legal or tax advice. Last reviewed November 2026 by Matthew Martinez.

Related: Napa Valley vineyards · Napa real estate guide · Yountville real estate guide · Oakville vineyards · Rutherford vineyards · Vineyard due diligence · Vineyard water rights · All vineyard and winery guides