Then name Yoro was originally means, bending knees. So, it means curved shaped because all the brunch rivers including Yoro River are highly curved all the way. During the Edo period, the Kanji Character changed to current ones.
Yoro Valley itself is very long valley, but there are two major hiking courses. One is for Kobundo Ruin which offers you great ruins of canal. Another one is around Awamata Falls. The Awamata Falls riverside walkway is one of the best hiking courses in Boso Peninsula. It offers you the great sound and colors of the river, beautiful trees and waterfalls. There are many water falls run in to the river at Awamata.
Awamata Waterfalls (粟又の滝, awamatanotaki) is the most popular waterfalls in Boso Peninsula. It is 30m high, 30m wide and 100 long. Awamata Waterfalls is also known as Yoro Great Falls ( 養老の大滝) because it is located on Yoro River (養老川). There is the riverside walkway for 2 km starts from Awamata Waterfalls. There are many small waterfalls and one of the best scenery in Chiba, especially either June with green leaves or autumn with autumn leaves.
Ruins of Kobundo(弘文洞跡)
...is the ruins of canal which connects Yuki River to Yoro River. It was used be huge hole, but in 1979, the roof was fallen down, and now, it has left the great valley, there.
Be aware for flooding when it has heavy rain. There are many evacuation area. Try not to go near the river or waterfalls during or after the heavy rains.