At a later period of the war Dearborn was promoted to be lieutenant-colonel and was present at the surrender of Lord Cornwallis at Yorktown in 1781. After this event he wrote in his journal: "Here ends my military life." He was, however, afterwards commissioned a major-general of militia by the State of Massachusetts, of which State he was a citizen. He became a member of Congress in 1801, and was appointed Secretary of War by President Jefferson. He remained in the cabinet of President Jefferson throughout the eight years of his administration.
In the War of 1812 General Dearborn was appointed senior major-general by President Madison, and rendered distinguished services on the Niagara frontier during that war. He died in Boston at the advanced age of seventy-nine years.
A portrait of General Dearborn is at the present time in the possession of the Calumet Club of Chicago, painted by Gilbert Stuart. John Wentworth once said: "One of the highest compliments paid to General Dearborn is the fact that whilst the names of so many of our streets, have been changed to gratify the whims of our aldermen, no attempt has been made to change that of Dearborn Street. Not only is this the case but the name Dearborn continues to be prefixed to institutions, enterprises, and objects which it is the desire of projectors to honor."
There was an interpreter at the fort, John Lalime by name, who was at enmity with John Kinzie, the Indian trader. One afternoon early in the year 1812, Mr. Kinzie had occasion to be at the fort, and when the gates were about to be closed for the night he passed out to return to his home across the river. Just after his departure Lalime also passed out at the gate, and knowing the state of feeling between the two men, Lieutenant Helm, who was the officer on duty, called out to Mr. Kinzie to beware of Lalime. The latter was following the other closely and his actions were threatening.
Lieutenant Helm had married Mr. Kinzie's step-daughter, Margaret McKillip, some years before, and the relationship thus existing doubtless caused a feeling of natural anxiety on the part of the officer for Mr. Kinzie's safety. When Mr. Kinzie heard the warning shout he turned suddenly upon the man following him and at the same time saw that he was armed with a pistol in his hand and a knife in his belt. Mr. Kinzie himself was totally unprovided with weapons, but notwithstanding, he grappled with Lalime at once. In the course of the struggle which ensued the pistol was discharged, though without harm to either antagonist. Both men attempted to get possession of the knife and both were wounded by it. Mr. Kinzie, however, succeeded in inflicting a fatal thrust upon his adversary, while he himself was covered with blood as a result of the encounter. Lalime fell dead upon the ground.
This tragic affair was witnessed by the people at the fort, and by a half-breed woman who was a servant in the Kinzie family from the door of the Kinzie house. As Lalime had many friends at the fort who at first thought that Mr. Kinzie had attacked him without provocation there was a movement to take Kinzie into custody; and fearing that a squad would be sent for this purpose, he concealed himself in the woods near his house, and soon after embarked in a boat with an Indian guide for Milwaukee, where one of his trading posts was located.
An inquiry into all the circumstances of the affair was made by the officers of the garrison, and a verdict of justifiable homicide was reached. Mr. Kinzie, hearing of this, returned to his home as soon as he had sufficiently recovered from his wound to do so.
It was said by Gurdon S. Hubbard in later years that Mr. Kinzie deeply regretted the killing of Lalime, and further, that he firmly believed the deed was committed in self-defence. Lalime was an educated man and was a favorite with the military people. He was buried on the north side of the river, and for many years thereafter the grave was enclosed with a small picket fence, which was cared for by Mr. Kinzie and his family.
When Captain Nathan Heald assumed command at Fort Dearborn, in succession to Captain Whistler, he entered upon his duties with much reluctance, owing to the remoteness of the post and the loneliness of its situation. He was a much younger man than his predecessor, being at the time thirty-five years of age and unmarried, and found himself associated with officers still younger than he was. A few days after his arrival at his new post he wrote Colonel Jacob Kingsbury, commandant at Detroit, that he was not pleased with his situation and could not bear to think of staying there during the winter. "It is a good place," he wrote, "for a man who has a family, and can content himself to live remote from the civilized part of the world."