This documentation explores the exceptional genealogical bond between the Levasseur and Ouellet families in Saint-Éloi, Quebec, during the early twentieth century. It primarily highlights four marriages between the children of Alphonse Levasseur and William Ouellet that occurred between 1907 and 1913. These unions resulted in a generation of double first cousins who share all four grandparents, a rare occurrence that impacts modern DNA analysis. Through census records and paternal lineage charts, the text traces the families' agricultural history and their migration from early pioneers to established households. The narrative combines historical data with maps and illustrations to provide a comprehensive portrait of a rural commu ...