The wine that Portland Monthly wine critic Conde Cox picked as the best Oregon wine to be released this year began its life as a grape vine planted in 1994. But it might not have existed at all without a law passed in 1973.

The grapes for more than two-thirds of our 50 best wines were grown within an 11-square-mile section of the Willamette Valley American Viticultural Area, or AVA—Oregon’s first official appellation, established in 1983. However, the more important moment in the history of Oregon wine occurred in 1975, when Oregon began requiring every city in the state to implement an urban growth boundary. The result: numerous hillsides on the outskirts of Salem, McMinnville, and Forest Grove that might have sprouted farms and McMansions instead were used for growing grapes. Between 2004 and 2006, the Willamette Valley gained six more appellations (shown on the map below), each an extraordinary microclimate for vineyards—and all largely preserved by Oregon’s unique system of managing urban growth.

KEY: Vineyard (Ranking)

1. Montinore Estate (42)
2. Cooper Mountain Vineyard (40, 48)
3. Et Fille: Kalita Vineyard (10)
4. Hawks View Cellars (3, 19)
5. Brick House (28, 34)
6. Bergström (8, 32)
7. ArborBrook (39)
8. 1789: Lachini Vineyards (2)
9. Penner-Ash Wine Cellars (21)
10. Lemelson Vineyards (20)
11. Laura Volkman Vineyard (38)
12. Et Fille: Nicholas Vineyard (11)
13. Chehalem (16, 41, 43)
14. Raptor Ridge (46)
15. Ken Wright: Abbott Claim Vineyard (4)
16. Archery Summit Winery: Red Hills Estate (1, 15)
17. McKinlay (50)
18. Vista Hills Vineyard (30)
19. Domaine Serene (6)
20. De Ponte Cellars (29)
21. Domaine Drouhin (17)
22. Eyrie Vineyards (37)
23. Stoller Vineyards (36)
24. Twelve (44)
25. Remy Wines (22)
26. Maysara (49)
27. Brittan Vineyards (12, 27)
28. Eminent Domaine (13)
29. Iota Cellars (9, 26)
30. Cristom Vineyards (7)
31. Ken Wright: Carter Vineyard (5)
32. Dukes Family Vineyards (24)