The tortuous and unnatural boundary between South Kerry (H1) and North Kerry (H2) is a cause of confusion to botanists (Webb 1980 Proc. R. lr. Acad. 80 B: 179-196). This is especially so in the region of the Lakes of Killarney; there the dividing line runs more or less north-south, with H1 to the west and H2 to the east. The division between H1 and H2 was established by Praeger (1896, Ir. Nat. 5: 29-38, 1901, Proc. R. lr. Acad. (3) 7) on the basis of existing barony boundaries. These baronies are shown in the map in Scully's Flora of County Kerry (1916 Dublin, Hodges and Figgis), and in the Ordnance Survey maps at six inches to a mile.
I have recently realised that there is an important discrepancy between the map in Praeger's Irish Topographical Botany (1901) and that in Scully (1916). The boundary between H1 and H2 south of the Upper Lake of Killarney shown by Praeger does not in fact correspond to the barony boundary. Instead, he shows a north-south division following the line of Galway's River and its southern tributary Ullauns River. The true boundary between the baronies of Dunkerron South and Magunihy, as shown by the Ordnance Survey maps and by Scully, lies about 1.3 km further west, for a north-south distance of 3.5km. (The barony boundary runs south from the Upper Lake through Lady's View, then turns sharply east near Glas Loughs, thus joining the line of Ullauns River).
As Webb (op. cit. pp. 182-183) makes clear, the map in Praeger (1901) must be accepted as the standard for the definition of the biological vice-counties of Ireland. This means that the barony boundary must be disregarded in the area in question: i.e., the boundary shown in Scully (1916) and Webb (op. cit. Fig. 2) and described in Webb (op. cit. p. 189). The map in Scannell & Synnott (1972 Census Catalogue of the Flora of Ireland, Dublin, Govt. Stationery Office), being a reproduction of that in Praeger (1901), is correct. It follows that these 1-km squares on the National Grid are mainly in H1 and not in H2: V 90 78, V 90 79, V 90 80 and V 90 81; H1 includes about half of the Upper Lake of Killarney, the district of Incheens, and the famous oakwood of Derrycunihy.
I am grateful for information and advice from Miss M. J. P. Scannell, Mr. B. O'Ciobhain of the Ordnance Survey Office, Dublin, and Professor D. A. Webb.
D. A. Webb (1980) The Biological Vice-Counties of Ireland Proceedings of the Royal Irish Academy, Vol. 80B, 179-196 (1980)