Finally, Gage put his plan into motion. The previous excursions taught him that this needed to be a quick strike, and secrecy was essential. Gage planned on a mixed force of elite Grenadiers and Light Infantry, picked from the several regiments in Boston. The Grenadiers were known to be fearless fighters and of big stock. While the Light Infantry tended to be smaller, they were less equipped so they could move fast. Both types of infantry were considered some of the most trained and effective troops. One possible problem was that these companies never served together since they were pulled from their various regiments. This could cause command issues if forced into combat. In command of these nearly 700 men, Gage placed Lt. Col. Francis Smith. Smith, a senior officer in the 10th Regiment of Foot, was chosen because he was cautious, prudent, and would not act rashly. Gage knew this was a precarious mission and wanted a level-headed man in command. Smith, one of the more overweight officers in Gage’s command, was not a dynamic leader. His ability to be flexible and think on the fly was questionable. Smith’s second in command was Maj. John Pitcairn of the Royal Marines. Pitcairn was considered a sharp officer and actually respected by many in Boston, even the Patriots.

Gage’s orders to Smith were direct. He was to march to Concord “with the utmost

expedition and secrecy to Concord, where you will seize and destroy all the artillery, ammunition, provisions, tents, small arms and all military stores whatever.” Gage also wanted to be sure the soldiers respected private property; their issue was with the rebels and their leaders, not the private citizens. They were also not to fire on any militia they encountered unless they were fired upon first. Gage knew that there might a possibility that armed militias would meet Smith’s force somewhere along the way as they had done previously in Portsmouth and Salem.

Left out of Smith’s orders were the capture of the Patriot leaders. One can only surmise why Gage did not carry out this directive from Dartmouth, but Gage knew the situation in Massachusetts better than his superiors. He might have wanted to avoid creating martyrs for the Patriot case. In either case, the men would cross Back Bay on long boats provided by the Royal Navy. From there, they would land at Lechmere Point and march through Cambridge, Menotomy through Lexington and to Concord. The other possible route, over the Boston neck, was deemed more hazardous and open to potential ambushes. The column wanted to keep its final destination a secret and crossing via water could possibly confuse the Patriot riders and spies that were surely out in the countryside after the first two false alarms that spring.

To try to prevent the Patriot riders from spreading the alarm, Gage ordered out a patrol of 25 men on April 18th to ride in the direction of Concord to cover all the major roads and intersections. As Gage told Smith, these men were “ordered out to stop all advice of your march getting to Concord before you.” Unfortunately, these men raised more suspicion than anything else. Locals began to wonder why these British men on horseback were out on patrol. Though these patrols did capture a few Patriot riders that night, they created more harm than good and added to the Patriot sense that something was about to happen on the night of April 18th.

The precision and preciseness of the Patriot and Sons of Liberty spy network was proven on the night of April 18th. Gage, proud of his highly guarded secret, found out quickly through some of his junior officers, that the mission was not a secret. Many of the men did know their “secret” destination was Concord. How this information was released is lost to history. Some argue Gage’s wife, Margaret, might have informed Dr. Joseph Warren about the expedition. Margaret, a native of New Jersey might have had possible sentimental feelings towards the Patriots. However, there is no hard evidence that she betrayed her husband. What is known is that Warren did have informants close to Gage and, possibly through paid information, Warren was able to procure this important information. The Patriot leaders also had other clues that something was going to happen on the night of April 18th. The moving of all the Grenadier and Light Infantry companies from the barracks to the Boston Common, as well as the assembly of the Naval long boats on Back Bay notified the Patriots that the British were planning a move of some sort. Either way, as the British units were assembling on the Boston Common, the Patriot system of alarm riders was put into action.