In 1699 Louis XIV commissioned Antoine de Lamothe Cadillac to establish a post on Detroit du Herie (strait of Erie) to protect the area from English intervention. In 1701 Cadillac established Fort Pontchartrain at Detroit. It was named in honor of Jérôme Phélypeaux, Comte de Pontchartrain, Louis XIV's minister of marine. The Fort was an arpent square (192 feet) with four bastions. The walled town was planned to contain Ste. Anne's Church/ Sacristy/Parsonage, a powder Magazine/Trade House, a guardhouse, an icehouse and 14 houses. However by 1711 only 10 buildings had been completed. By 1760, the end of the French regime, Fort Detroit as it became known, had grown to 350 x 840 feet.
Cadillac invited friendly Indian nations to build their villages near the Fort. The Ottawa and Huron from Michilimackinac and the Potawatomi from the St. Joseph River valley settled near the Fort. The Chippewa came from various points to Harsen's Island at the mouth of the St. Clair River, and the Miami from the St. Joseph River valley, settled at the mouth of the Maumee River. During the winter of 1701-02 there were 6,000 Indians living in the Detroit area. The Potawatomi village was located a short distance below the Fort, the Huron village was nearer to the Fort at the mouth of the Savoyard River and the Ottawa located across the River (Walkerville, Windsor Ontario). The Miami eventually moved away.
In 1703, some Ottawa chiefs were invited to Orange (Albany, NY) by the British, during Queen Anne's War, who attempted to convince them that Detroit was established to enslave the Indians. It had some partial effect as when Cadallic was gone from the Fort, some of the Ottawa attacked the Fort, a portion of the palisades, Cadillac's house, Ste. Anne's Church, the residence of the Priest and another house was burned to the ground, but no lives were lost. Friendly Indians cooperated with the French in driving off the attacking party. The Indian allies assisted in rebuilding the houses and gave Cadallic 100 bushels of corn as partial reimbursement for the losses.
In 1706 some Ottawa attacked a party of six Miami Indians, and five of the six were killed. The one who escaped gave the alarm to the Miami village, all retreated to the Fort for protection. The trouble was caused when a Miami dog had bitten an Ottawa and as a consequence of kicking the dog he was so severely beaten by Commander De Bourgmont that he died. Father de L'Halle, the Recollet Priest was walking in his garden at the time of the incident and was captured by the Ottawa. A Chief ordered the Priest released, but when Father de L'Halle was about to pass through the Fort gate he was shot to death by an Ottawa. De Bourgmont ordered the garrison of 15 soldiers to fire. The results killed about 30 Ottawa. The Ottawa tried to get the Huron to join them. When they refused the Ottawa attacked the Huron village, but were repulsed. For a month the Ottawa kept the Fort under siege before agreeing to a peace. Cadillac asked Governor Vaudreuil to intercede. The principle Ottawa Chiefs were called to Quebec, they agreed to surrender Le Pesant the leader of the uprising to Cadillac to be executed. When Le Pesant was turned over, Cadillac pardoned him on account of his age and as a matter of policy. The Miami disagreed with the pardon and went to war killing three Frenchmen and destroying some property. The Miami convinced the Huron to join them and the Iroquois also assembled a war party to aid them. Cadillac asked for more troops and made peace with the Miami. The Miami viewed Cadillac's action as a weakness and violated the treaty. Cadillac raised a larger force and marched against them, compelling the Miami to accept his terms.
In 1710 The French and British were again at war. The Five Nations of the Iroquois sided with the British. Representatives from the Fox Nation located between Green Bay and Lake Michigan visited the Five Nations in 1711, formed an alliance and promised the British that they would capture Detroit. They enlisted the Kickapoo and Mascouten to help with their plan.
In early May 1712 a large body of Fox and Kickapoo, showed up at Detroit, camped very near the Fort and began throwing up earthworks. Commander Dubuisson ordered them away, but they refused. There were only 30 soldiers in the garrison and the Huron and Ottawa were out on the winter hunt. Dubuisson ordered the garrison's supply of wheat, which was stored in a house on the outside, into the Fort and the destruction of the Church and other buildings outside the Fort that the Fox could have used to their advantage.
On May 13, 1712 De Vincennes arrived with reinforcements and the Indians allied with the French returned from the winter hunt. The French and their allies now besieged the Fox. An Ottawa war party intercepted 150 Mascouten on their way to join the Fox. After several days the Fox attempted to gain a truce, which failed. At one point the garrison moved one of its breech-loading swivel cannons up on to a scaffold in the Fort to destroy a firing platform that the Fox had erected. The Fox then tried to destroy the Fort with fire arrows, which the French were able to extinguish with water stored in two large pirogues that had been filled for that purpose. On the night of the 19th day of the siege, the Fox withdrew. The French and their allies pursued, which resulted in Fox losses. The Fox succeeded in returning to the Green Bay area. The Fox again attacked Detroit in 1717 but were repulsed without loss. While the peace was ruffled in 1737 and there was a plot to attack Detroit in 1747 by a Huron faction, the Fort was never attacked again during the French period.
The Jesuits of Quebec established a Huron mission at Detroit in 1728. It was located across the River from the Fort (Sandwich, Windsor, Ontario). The Canadian farmers that settled on the South shore attended services at the Mission Church. In 1736 a store and warehouse were established at the Mission. The Hurons relocated their village in the vicinity of the Mission in 1747. Father Potier regularly read the newspapers from Europe (Potier was a missionary at the Mission 1744-1781).
Detroit was an important post, serving as the supply center for the Southern Canadian Forts connecting to the Illinois country. It was maintained as a King's post where the Crown operated the Trade house and paid the expenses of the garrison in order to keep the French trade goods competitive with British prices. The lands along the river, on both sides, in the area of Detroit became successful farms. The farms are known as ribbon farms being very narrow and quite long, they varied from four to six hundred feet wide and from one and half to three miles deep. The longer growing season and location of Detroit allowed it to export produce within the colony. Farm products included wheat, oats, corn, peas, pears, peaches, apples, cattle and oxen, hogs, poultry and horses. Windmills were also common along the river shore. Occupations at Detroit included the Post Surgeon, Chaplain, missionary, soldier, merchant, trader, voyageur, blacksmith, gunsmith, stonemason, harness maker, tailor, cartwright, shoemaker, miller, farmer, shipwright, baker, laundress, slave, Indian interpreter, keeper of the Kings woods, King's Gardener, Sub-Intendant/Royal Notary and Commander.
In 1754 the military strength at Detroit included 35 Marines, 200 Militia (Milice) and about 300 Indians from the surrounding towns. The armament of Fort Detroit consisted of several iron breech loading swivel guns, 2 iron three livre (pound) cannons and a few small mortars. There was a ship building yard in the Rouge River area near Detroit.
In 1759 Detroit residents contributed heavily to the relief column sent to Fort Niagara then under siege by the British. All members of the column were killed or captured by the British at the battle of La Belle Famille near Fort Niagara.
By the end of the French period, Detroit had grown to be the third largest town in the Colony of Canada, had a Town Major and three companies of Marines.