The Paulist Fathers are a Catholic order founded in the United States in 1858. Their apostolate is the conversion of Americans to Roman Catholicism. Beginning with their missions as Redemptorist priests in 1851, the Paulists kept records of the missions that they held, the number of converts they made, and the number of confessions they heard (which is roughly a count of the number of people who attended the missions).
This map, which is part of my dissertation, was made by Lincoln Mullen in D3.js (code here). Historic state boundaries are from NHGIS. The Paulist missions are recorded in Chronicle of the Missions Given by the Congregation of Missionary Priests of St. Paul the Apostle, six manuscript volumes, Office of Paulist History and Archives, North American Paulist Center, Washington, DC.
N.B. From 1866 to 1870 the Paulists had too few priests to hold any missions. The Paulists kept summary statistics from 1851 to 1906, but they did not keep detailed records for every year, so the map appears blank for some years.