Two battles were fought at Tarain, near Thanesar in what is now Haryana, between Prithviraj Chauhan and Muhammad of Ghor. Prithviraj won the first in 1191. He lost the second in 1192 and was killed or executed shortly after.
The second battle opened northern India to the Ghurids and led directly to the Delhi Sultanate, established in 1206 under Qutbuddin Aibak.
The site is on the road between Delhi and Punjab, which is the same road that carries Panipat, Kurukshetra, Sirhind and Karnal. Every invasion and every decisive battle for control of northern India for two thousand years was fought within a hundred kilometres of the same stretch of the Grand Trunk Road.
That is a fact of geography. The Yamuna and the Thar close the gap and everything has to pass through it.
Punjab was the corridor, and its history is what a corridor's history looks like.
The Persian accounts and the Rajput bardic tradition give completely different versions of both battles, down to how Prithviraj died. The Prithviraj Raso, the source most often quoted, was written long afterward and is not a record of the events.
The consequence was the establishment of Turkish rule at Delhi. The Punjab was the corridor it came through and the first province held.
The field is near Taraori in Karnal district. There is nothing on the ground and no archaeological work has fixed the site.