BlackAnkle Vineyards. Located in Mt. Airy, just 40 minutes from Baltimore. They can accommodate 100 people indoors and more than that in tents.
Boordy Vineyards. Located in Hydes, MD, just 15 minutes north of Baltimore. They can accommodate 70 people.
Fiore Winery. Located in Pylesville, MD, in northern Harford County. Indoors can accommodate up to 150 and outdoors up to 1000 guests!
There are many more in the area, check out this website for more information: wineryweddingguide.com