Park your bike or car, but not your boots, at the top of Old Road, and head south into the field, and down into the trees. Shotover Country Park is criss-crossed with paths that lead you into the wood (and out of it, but mostly into it). You should expect to get a bit lost, so you'll need an accurate GPS. In wetter weather or winter it may be muddy, so plan to slither and slide.
Cache placed with the kind permission of Oxford City Council.