The success of the royal arms in Monaghan, Leitrim, and Fermanagh, kept pace with the progress of Hamilton and Berwick. The insurgents were everywhere driven from the open country, and compelled to take refuge in Crom and Enniskillen. The garrison of Sligo, consisting of 3,000 foot and 1,000 horse, under Lord Kingston, withdrew to Ballyshannon, which commands the entrance to Lough-Erne; and towards the beginning of May, there remained no place of any significance in their possession but the fortified towns of Enniskillen and Derry. But the defenders of the latter place had made good use of the temporary cessation of hostilities after the battle of Cladiford. Their outlying posts were immediately abandoned, and troops came in daily from all quarters. Culmore, a strong post which guarded the entrance of the Foyle, and which they had held through the winter, was evacuated on the approach of the Jacobite army, and its garrison of 1,500 men, under Captain Murray, after a hazardous march through the mountainous country to the west of the river, succeeded in getting safely within its walls. The accession of these forces gave a new impulse to the flagging spirit of the defenders. Governor Lundy, being suspected of Jacobite tendencies, was at once deposed, and a military council was constituted, of which Murray, the Reverend George Walker, and Colonel Baker, were the ruling spirits. The town of Derry stands on the western bank of the river Foyle, about five miles above its expansion into a lough of the same name. It is situated on an oval-shaped hill; the houses, rising tier over tier, look very picturesque to one approaching it from an eastern direction; but to the west it is overlooked by an irregular line of hills, stretching far back into the County of Donegal. Since the time of the Revolution, it has been greatly extended in all directions, but was then confined to the hill already mentioned, and was encompassed by a wall of immense strength, and about a mile in circuit. It was founded by King James I., in 1607, as a refuge to the settlers, whom he sent from England and Scotland, to the exclusion of the native race; and, by a sort of retributive justice, it helped to complete the ruin of his house, in the person of his grandson, but eighty years later. After the departure of the king for Dublin, the Irish generals proceeded to invest this important position, and, by the 20th of April, had made the following disposition of their forces: The fort of Culmore, which stands about five miles below the town, was occupied by a small garrison after its evacuation by Captain Murray, and the river was obstructed by a boom a little higher up. Hamilton, with about one thousand horse and foot, established his camp some two miles from the walls of the garrison; General Ramsay, with four battalions, took up a position at Hollywell Hill, nearly the same distance to the west; Brigadier Wauchop, with two battalions, a squadron of horse and two