The earliest iron implements found in Wales come from Llyn Fawr at the head of the Rhondda Valley, where objects apparently deposited as votive offerings include three made of iron: a sword, a spearhead and a sickle. These items are thought to date to about 650 BC, and while the sword appears to be imported the sickle is an imitation of a native bronze prototype. The Iron Age saw the building of hillforts which are particularly numerous in Wales, examples being Pen Dinas near Aberystwyth and Tre'r Ceiri on the Llŷn Peninsula. The earliest distinctively Iron Age settlement in Wales is considered to be Castell Odo, a small hillfort near the tip of the Llŷn Peninsula, dated to about 400 BC. The largest hillforts are most numerous along the eastern border of Wales, with some large examples also found in the lowlands of north-west Wales. In the south-west, by contrast, hillforts are very numerous but mainly small, with an area of under 1.2 hectares.