HATFIELD, a market-town of the county of Hertford, in the hundred of Broadwater, twenty miles from London. It stands on the side of a hill. The church is remarkably neat; but the most remarkable object is the magnificent seat of the Marquis of Salisbury, with the beautiful park in which it stands. It was formerly the palace of the Bishop of Ely, but has been much adorned and improved by the noble family that now possesses it. There is a good market on Thursday. The population amounted in 1801 to 2442, in 1811 to 2677, in 1821 to 3215, and in 1831 to 3593.