Kilkenny is a township in Coös County, New Hampshire, United States. It lies entirely within the White Mountain National Forest. As of the 2020 census, the township had a population of zero.
In New Hampshire, locations, grants, townships (which are different from towns), and purchases are unincorporated portions of a county which are not part of any town and have limited self-government (if any, as many are uninhabited).
The town was granted to Jonathan Warner and others on June 4, 1774, containing . In 1840 it contained 19 inhabitants, and in 1856 it had 19 inhabitants and an area of , with a value of $20,000. It was named after the town and county of Kilkenny in Ireland.
Kilkenny once included a large portion of what is now the eastern edge of Jefferson, tapering south into the area of Jefferson Notch at the foot of Mount Mitten. This included much of the area known as "Jefferson Highland" on the Portland Road (present-day U.S. Route 2). By the 1870s, maps were showing the southern edge of Kilkenny as a line extending the border between Jefferson and Lancaster. 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. Deeds in this area often refer to the "Kilkenny Addition".
On the 1935 topographic map, the "Upper Ammonoosuc Trail" crossed Kilkenny along Priscilla Brook and through the pass from the Keenan Brook area of Randolph, north of Pliny Mountain. This trail has since been abandoned, although a 2002 atlas of New Hampshire shows a "Priscilla Brook Trail" in the same location.
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. On the 1896 topographic map, there was a B&M railroad spur up much of Garland Brook, to an elevation of . By 1935, the tracks were gone.
According to the United States Census Bureau, the township has a total area of , of which , or 0.08%, are water.
Kilkenny is home to Mount Waumbek of the Pliny Range and Mount Cabot of the Pilot Range, each over high (see Four-thousand footers), as well as several other peaks over . The summit of Mount Cabot is the highest point in Kilkenny, at above sea level. The township is entirely within the Connecticut River watershed. 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.
As of the 2020 census, there were no people living in the township.