While it certainly seems to explain the existence of certain hills at the time, there isn't any known landmark to attach this event to.
The battle strongly appears to have taken place in Westmeath, between Athlone and Mullingar, but the hills in question don't seem to be identified.
After attempting collect a bunch of references to known locations of the Tain, I came across a recently written paper including maps explaining, and proposing changes to, the accepted route of the Tain: The Route of Táin Bó Cúailnge Revisited, by Paul Gosling.
Please do go take a look at the map labelled Figure 4 (I have intentionally not reproduced it here, per the Academia.edu licensing terms).
Some locations near the battle can be established clearly and easily:
Ath Luane - Modern Athlone, a city in County Westmeath - Where Donn Cuailnge leaves Finnbenach's loins immediately after the battle in question.
Ath Firdia - Modern Ardee, a city in County Louth (Complete with local monument) - The location of Cuchullain and Ferdiad's combat.
At Ath Firdia, the Connacht army is making a bee-line back to Cruachan with their prize in tow (harried by Cuchullain along the way, of course). Accepted opinion seems to place the final battle squarely in County Westmeath, somewhere generally between the modern cities of Athlone and Mullingar. The paper fills in the established locations of the camps of Ulster and Connacht:
And the author gives one location as the most likely location of the battle, as well as giving mention to a second possible location posited in an older resource, supposed supported by local tradition:
The two are less than 10 km apart, so pretty close. No statement as to the hills in question though. A speculation can be found here or there, but nothing that seems worth crediting. It's not too hard to see the problem. The author of the above paper describes the surrounding areas as "gently undulating enclosed farmland". Indeed, taking a quick look at a topographic map of the vicinity:
Which reveals not much going on. Ushnagh Hill seems to be the most dramatic hill in the area. It's the gentle incline just to the right of the "Killare" label on the map. The hill does appear to have quite a storied history, but I can't find any compelling reason to assume it is one of those mentioned in the story.