Hertfordshire is a county in south-east England, immediately north of London. It has a population of 975,000. Its economy is largely tied to that of the capital, but the town of Hatfield has an aerospace industry and University. The area also has a significant number of farmers, and has some sand and gravel quarries. Major towns include Watford, Hemel Hempstead, St Albans, Hitchin, Letchworth, Welwyn Garden City and the county town Hertford.