By the 1870s, maps were showing the southern edge of Kilkenny as a line extending the border between Jefferson and Lancaster.

[4] The 1896 topographic map, however, shows that the boundary had again been adjusted several miles south, to include Mount Waumbek and Pliny Mountain, uninhabited areas.

The Willard Bowl north of Mount Waumbek, drained by Garland Brook, was considered as a site for development of a ski area in 1971, when it was owned by former governor Hugh Gregg.

The summit of Mount Cabot is the highest point in Kilkenny, at 4,160 feet (1,270 m) above sea level.

The southern end of the township, as well as the west side of the Pilot Range, drain west via Fox Brook, Bunnell Brook, Garland Brook, and Priscilla Brook to the Israel River, which joins the Connecticut at Lancaster, while the northern end of the township, including the east side of the Pilot Range and its north end, drain to the Upper Ammonoosuc River, which flows north and west to join the Connecticut at Groveton.