Sir: It is with the greatest pleasure I inform you that, on Sunday last, the seventeenth instant, about nine o'clock in the forenoon, the ministerial army evacuated the town of Boston, and that the forces of the United Colonies are now in actual possession thereof. I beg leave to congratulate you, Sir, and the honourable Congress, on this happy event, and particularly as it was effected without endangering the lives and property of the remaining unhappy inhabitants. I have great reason to imagine their flight was precipitated by the appearance of a work which I had ordered to be thrown up last Saturday night on an eminence at Dorchester, which lay nearest to Boston Neck, called Nook's Hill. The town, although it has suffered greatly, is not in so bad a state as I expected to find it; and I have a particular pleasure in being able to inform you, Sir, that your house has received no damage worth mentioning. Your furniture is in tolerable order, and the family pictures are all left entire and untouched. Captain Cazeneau takes charge of the whole until he shall receive further orders from you. As soon as the ministerial troops had quitted the town, I ordered a thousand men (who had had the small-pox), under command of General Putnam, to take possession of the heights, which I shall endeavour to fortify in such a manner as to prevent their return, should they attempt it. But as they are still in the harbour, I thought it not prudent to march off with the main body of the army until I should be fully satisfied they had quitted the coast. I have, therefore, only detached five regiments, besides the rifle battalion, to New York, and shall keep the remainder here till all suspicion of their return ceases. The situation in which I found their works evidently discovered that their retreat was made with the greatest precipitation. They have left their barracks, and other works of wood at Bunker Hill, &c., all standing, and have destroyed but a small part of their lines. They have also left a number of fine pieces of cannon which they first spiked up, also a very large iron mortar, and, as I am informed, they have thrown another over the end of your wharf. I have employed proper persons to drill the cannon, and doubt not I shall save the most of them. I am not yet able to procure an exact list of all the stores they have left. As soon as it can be done, I shall take care to transmit it to you. From an estimate of what the quartermaster-general has already discovered, the amount will be twenty-five or thirty thousand pounds.