HELMSTEDT, a town of the wapentake of Rydall, in the north riding of the county of York, and 218 miles from London. It is on the river Rye, in a beautiful valley. It is well built, and had formerly a strong castle, which was demolished by Cromwell. There is a good market, which is held on Saturday. Near it are the ruins of Revaux Abbey, converted into a splendid modern mansion. The population amounted in 1801 to 1449, in 1811 to 1415, in 1821 to 1520, and in 1831 to 1485.