The northern limits of ancient China were defined by the Great Wall which meanders for nearly 5000km from east to west.

古代中国的北方界线就是万里长城，长城由东向西绵延5千公里。

It lies just beyond the northern limit of the higher portion of the range between the main axis and a spur that puts out on the east side from near the head of the Carson River.

它位于主轴线和从卡森河源头附近向东延伸的支线之间的范围较高部分的北限之外。