Marguerite was born on May 24, 1676 in Montreal. She is the ninth child of Michel Messier and Anne Lemoyne. At three years old, Marguerite moved with her parents to Varennes. Less than two months after her fourteenth birthday, on May 24, 1690, she married, in Boucherville, Pierre LeSueur, an explorer, a dealer, a woodsman and judge who marked  history in New France. At her wedding, Michel gives her the fief of La Guillaudière as her dowry, beside the Seigneury of Cap St-Michel, he bought a few years earlier. It was in Montreal, on St-Paul street where the couple moved. From this union were born a son and four daughters:

Mary Anne, on February 15, 1693;

Louise Margaret, on June 3rd, 1694;

Mary, on April 21, 1696;

Jean-Paul, on June 1, 1697 and he died on October 13, 1751 in La Mobile, Louisiana.

Margaret LeSueur, on July 4, 1699.

They are all baptized in the church of Notre-Dame of Montreal.

Marguerite LeSueur married Nicolas Chauvin, Sieur de LaFresnière, son of Pierre and Martha Hautreux, on July 23, 1724 in Mobile.

Marguerite does not know the married life for a long time. She must ensure the affairs of her husband; he is often left to explore new lands. For business, Pierre LeSueur travels between France, New France and Louisiana. He founded some forts on the Mississippi, looking for minerals and made fur trades. In 1702, he is in France and asked authorities the permission to get his family to "La Mobile" in Louisiana. The agreement is accepted by a royal memorandum sent to Vaudreuil, dated July 14, 1704.

Marguerite does not wait for official permission to leave. The Great Peace of Montreal, signed by Mr. de Callières with all the Indian tribes of Eastern America, made ​​the journey less perilous.

To get in Louisiana, she has to use at maximun the beautifull season of Summer. In spring 1704, Marguerite, aged twenty-eight, is busy preparing for her departure. On April 30, she is committed with a notary and hired François Benoît, Julien Choquet and Antoine Foisy for escorting her and her five children to "La Mobile". The contract stipulates that they must serve and obey her until the arrival in Louisiana. They will be fed and receive a salary; at destination, then she will give them a canoe to return to Canada. It is also mentioned that the trip should last one year with a renewal clause if necessary.

On May 2, Marguerite committed her brother Jean-Michel. He will accompany the group to the destination. They leave Ville-Marie with fellow travelers in early May, en route to the Gulf of Mexico.

At the end of March 1705, ten months after their departure, travelers sail on the Illinois River near the Mississippi. At Fort Pimitoui, they stop where the presence of Marguerite is noticed. All want to see this woman. Comments are eloquent. Native Indians say: "When Father Gravier, our missionary, spoke of the Virgin Mary as a beautiful woman, we would not have thought one day to meet a woman who has the beauty of the Mother of God described by our missionary. Children of this woman are equally as beautiful as the infant Jesus depicted in images."

An Indian woman, who saw the traveler, made ​​the following remark: "Compared to her, ours are monsters." In order to have a little peace, the commander of the place asked Marguerite to stand at the gate of the fort. She is sitting there for two days, outside the fort, to satisfy people's curiosity. A description of Marguerite is given to us in the memoirs of De Gannes. This document, now preserved in Chicago, which the author is Pierre des Liettes, described her as a person "very large, slim, very white, very elegant and a pretty well face."

On arrival in La Mobile, her troubles are not over yet. She learns that her husband Pierre LeSueur died at sea in the summer of 1704. His brother Jean-Michel and her daughter Marguerite Louise (born on June 4, 1694 in Montreal) also died on arrival at the Mobile. Here is a letter sent by Marguerite to Maurice Blondeau, a Montreal merchant.