MAINSFORTH, a township in the parish of BISHOP'S-MIDDLEHAM, north-eastern division of STOCKTON ward, county palatine of DURHAM, 8 miles (S.S.E.) from Durham, containing, 44 "inhabitants. The Little Skerne runs through the township': this rivulet was anciently diverted from its original course to form a deep fosse round a circular fortification, still called the Mainfort, situated on a commanding eminence, and supposed to have been successively occupied by the Romans and the Danes; it comprises an area of about sixteen, acres, exclusively of out-works, of which vestiges have frequently been discovered. Some years ago a pair of moose deer horns was found in a cave called the Dane's hole, on the summit of the fort. On an adjoining hill is an old house, called the Swan-house, where certain dues to the corivent of Durham,'and afterwards to the chapter, were formerly paid.. Limestone abounds in the parish.