district, administrative and historic county of Suffolk, England. It takes its name from the vegetation of the area, which is a mixture of heathlands and forest plantations characteristic of the larger region known as the Breckland. Mainly rural, the district occupies the northwestern corner of Suffolk. It includes Newmarket town, renowned for its horse racetracks and gallops, upon which the town so largely depends for its livelihood. Area 146 square miles (378 square km). Pop. (2001) 55,514.