Seward is an unincorporated community in Winnebago County, Illinois, and is located west of Rockford. It is part of the Rockford, Illinois Metropolitan Statistical Area. In early 2007, a leak at Seward Ag caused the release of 38,000 to 40,000 pounds of anhydrous ammonia gas. This resulted in a full evacuation of the village until the next day. Ten people were treated for throat irritation at Rockford hospitals. Three cows and four pigs were killed because of exposure to anhydrous ammonia.