The English did have a foothold within Ulster, around Carrickfergus north of Belfast Lough, where a small colony had been planted in the 1570s; but here too the terrain was unfavorable for the English, since Lough Neagh and the river Bann, the lower stretch of which ran through the dense forest of Glenconkeyn, formed an effective barrier on the eastern edge of the O'Neill territory. A further difficulty lay in the want of a port on the northern sea coast where the English might launch an amphibious attack into O'Neill's rear. The English strategic situation was complicated by interference from Scots clans, which were supplying O'Neill with soldiers and materials and playing upon the English need for local assistance, while keeping an eye to their own territorial influence in the Route (modern County Antrim).