On August 1, 1869 the first Mass to be held in Lassen County was at the home of Ned Mulroney near Susanville, with the 27-year-old Father Charles Lynch officiating. Since a circuit priest had to cover a large territory in Northeastern California and Nevada, Mass in many instances was only held once a year when the priest made his rounds.
In the 1880s with a larger Catholic population, and the Diocese territory smaller, Mass was be held in the Lassen County area twice year. There was also a movement to have their own house of worship instead of the courtroom in the Lassen County Courthouse or the hall in the Steward House Hotel.
This changed in the spring of 1892, when William Cain, a non-Catholic, donated a parcel land across the Susan River on Richmond Road, the current site of Poulsen’s Welding. In May construction began, the labor from church volunteers. As Father Thomas Horgan later recalled the driving force for the church came from three families—Bantley, Neuhaus, and Mulroney.
The new church had a seating capacity of 120, quite ample for their being about 100 parishioners. On June 26, 1898 Bishop Thomas Grace dedicated the Susanville church as the Church of the Sacred Heart.