Total population (1990 census): 46733
County seat: Mason City
Crop Statistics (1997 US Census of Agriculture)
| Cereals | Farms | Acres | Yield | |
| Maize=Corn | 563 | 137695 | 19318381 bu | |
| Oats | 76 | 1301 | 95053 bu | |
| Grain Legumes | Farms | Acres | Yield | |
| Soybean | 579 | 120639 | 5196050 bu | |
| Forages | Farms | Acres | Yield | |
| Total Hay* | 190 | 3529 | 8161 tons, dry | |
| Alfalfa Hay | 152 | 2212 | 5454 tons, dry | |
| Small Grain Hay | 31 | 583 | 1134 tons, dry | |
| Tame Hay | 35 | 508 | 1122 tons, dry | |
| Wild Hay | 10 | 79 | 66 tons dry | |
| Grass Silage | 8 | 147 | 1152 tons, grn | |
| Corn for Silage | 44 | 1115 | 19403 tons, grn | |
| 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 | 15 | 333500 | 323 | 3569 |
| Nursery, Floriculture, Vegetable and Flower Seed Crops | 3 | X | 14 | X |
| Florculture Crops | 7 | D | D | D |
| Bedding/Garden Plants | 7 | 270500 | D | D |
| Potted Flowering Plants | 3 | D | D | 130 |
| Cut Christmas Trees Harvested | 4 | X | 21 | 23 |
| Nursery Crops | 3 | D | D | 566 |
| Sod Harvested | 3 | X | 169 | 137 |
*Alfalfa, grass silage, green chops etc.
D=Withheld to avoid disclosing data for individual farms.
X=Not applicable.