Total population (1990 census): 215677
County seat: Manassas
CropSELECT
Cereals, Pseudocereals, Oilseeds
Industrial, Fiber
Forages
Vegetables
Fruits and Nuts
Herb, Aromatic, Medicinal, and Bioactive
| Cereals | Farms | Acres | Yield | |
| Maize=Corn | 21 | 2853 | 212759 bu | |
| Wheat | 16 | 833 | 35477 bu | |
| Barley | 4 | D | D | |
| Grain Legumes | Farms | Acres | Yield | |
| Soybeans for Beans | 15 | 2426 | 73924 bu | |
| Forages | Farms | Acres | Yield | |
| Total Hay* | 152 | 10295 | 15692 tons, dry | |
| Alfalfa Hay | 15 | D | D | |
| Tame Hay | 123 | 7787 | 11932 tons, dry | |
| Wild Hay | 27 | 1584 | 1864 tons dry | |
| Grass Silage | 9 | 613 | 3338 tons, grn | |
| Corn for Silage or Green Chop | 14 | 1643 | 19600 tons, grn | |
| Vegetables | Farms | Acres | Yield | |
| Herbs, Fresh Cut | 3 | Z | ||
| Tomatoes | 5 | 1 | ||
| Fruits and Nuts | Farms | Acres | Yield | |
| Apples | 5 | 5 | 182 trees | |
| Grapes | 3 | 3 | D | |
| Other Crops | Farms | Acres | Yield | |
| Herbs, Total | 3 | Z | X | |
| Nursery and Greenhouse Crops, Cut Christmas Trees Harvested, Mushrooms, and Sod Grown for Sale | Farms | Sq. ft. under glass or other protection | Acres in the open | Sales ($1,000) |
| Nursery and Greenhouse Crops | 10 | D | 982 | 3173 |
| Nursery, Floriculture, Vegetable and Flower Seed Crops | 5 | X | 495 | X |
| Floriculture Crops | 3 | D | D | 7 |
| Cut Christmas Trees Harvested | 3 | X | 6 | 55 |
| Sod Harvested | 4 | X | 920 | 3062 |
*Alfalfa, grass silage, green chops etc.
D=Withheld to avoid disclosing data for individual farms.
X=Not applicable.
Z=Less than half of the unit shown.