For one year, from late in 1840 until the 17th of September 1841, Father John Guéguen was assigned specifically to Will County and the Canal Missions. The Catholic Almanac for this time listed Father Guéguen as attending Corkstown. The fact that Father Guéguen had this assignment indicates that Father Du Pontavice was freed to devote more time to Joliet and that the canal area was active enough to occupy the time of another priest.

John Guéguen was a native of Brittany, France, born on the 12th of January 1814. He did preparatory studies at the seminary at Plouguerneval. Upon completion of that work it was on to the grand seminary at St. Brieux. When Bishop Bruté came to St. Brieux to enlist seminarians for work in America, John Guéguen was struck by his call.

In the fall of 1839 John traveled across the Atlantic Ocean with the group of twenty missionaries brought from France by Bishop Bruté. He achieved subdeacon status on the 18th of January 1840, moving to deacon on the 5th of April 1840. Bishop De La Hailandière ordained him on the 16th of August 1840. Father Guéguen had the following insight shortly upon his arrival in America and while he was traversing northern Indiana: "I had had many surprises in a very short time. I had just come from France where the regulations against women having anything whatever to do with divine service were most strictly enforced with excessive rigor, and here a woman had inspected my authorization, had helped me hear confession [as translator] and made my sermon reach the minds of all my hearers. Yet, what of it? I had done missionary work as I had never dreamed of, and there and then I came to a conclusion which I turned into a fixed resolution, that I would never oppose any American custom, no matter how strange and peculiar it might be, provided it was not opposed to the ten commandments and did not contradict the teaching of the gospel, for my recent experiences made me feel that that would be the way to do the most good."[Sister Mary Borromeo Brown. The History of the Sisters of Providence of St. Mary of the Woods, Vol.1. New York. 1949 P.130]

During 1842 Father Guéguen was reassigned to Irish Settlement in Shields Township, Lake County, Illinois. From this point he would fan out to McHenry, Kane and Dekalb Counties. Along Carduaz Road, near Libertyville Road, Father John occupied a log cabin from which he toured a circuit around northern Illinois: "Starting from his log hut on horseback, vestments and altar furniture in his saddlebags, westward to Freeport, sometimes to Galena, then south and east to Joliet and north by way of Chicago to his log hut in the bush, visiting settlers wherever he could find them, baptizing the children, saying Mass and speaking words of encouragement to the people 'in the wilderness'." [Joseph J. Thompson. The Diamond Jubilee of the Archdiocese of Chicago. DesPlaines, IL. 1920, p.203]

These tours would take about four months. They were his work until the formation of the Diocese of Chicago. His work typifies the spiritual artistry of the "Holy Tramps" who spread out to cover any and all souls in need of God's word and light. All of this was the fruit of seeds planted at the Illinois Canal. Upon Father Guéguen's return to the Diocese of Vincennes came a new assignment at St. Mary's Church in Daviess County, Indiana. For fourteen years between 1852 and 1867 he served as president of the diocesan seminary at Highland, Indiana. The last fourteen years of his life were spent as chaplain to the Sisters of Providence at St. Mary-of-the-Woods, Indiana. He died and was buried among them on the 17th of December 1893.