Qin dynasty
Note: King Zhaoxiang of Qin (秦昭襄王) had already been ruling Qin for 51 years when Qin annihilated the Zhou dynasty; however the other six warring states were still independent regimes. Some Chinese historiographers thus used the next year (the 52nd year of King Zhaoxiang of Qin) as the official succession from the Zhou dynasty.
Yan (state)
In 222 BCE, Liaodong fell as well, and Yan was totally conquered by Qin. Yan was the third last state to fall, and with its destruction the fates of the remaining two kingdoms were sealed. In 221 BCE, Qin conquered all of China, ending the Warring States period and founding the Qin dynasty.