Maiden Castle is an Iron Age hillfort on a wooded promontory above the River Wear, southeast of Durham's historic core. It is not a castle in the Norman sense; the surviving interest is in the earthwork, the defensive position, and the way the river landscape explains why people fortified this spot long before the cathedral and castle made Durham famous.
The site is best for walkers who enjoy archaeology in the landscape. There are no visitor facilities and the remains are subtle, but the route out along the river gives a useful counterpoint to the compact medieval city. Go with a map or GPS, since the fort can feel more like a wooded rise than an obvious monument at first glance.