Yes, Dutch Henry Winery has a picnic area. Call ahead to confirm any corkage fee or outside-food policy. Some estates allow you to bring provisions; others have restrictions. Arrive early on weekends to secure a good spot.
Dutch Henry Winery is in Calistoga, CA, in the Calistoga wine region. Phone: (707) 942-5771. Confirm hours before visiting. Winery schedules vary seasonally.