Newport Hundred was a hundred in the county of Buckinghamshire, England. It was situated in the north of the county and forming the boundary with the counties of Bedfordshire and Northamptonshire. It was commonly known as 'the three hundreds of Newport' because it amalgamated three earlier (11C) hundreds: Bonestou, Moulsoe and Siglelai (or Seckley). Its modern equivalent is the Borough of Milton Keynes, which covers almost exactly the same area (plus a little of the former Winslow Hundred which was one of 18 ancient hundreds amalgamated under the administrative control of Cottesloe Hundred.