The Diocese of Syracuse includes seven counties: The first Catholic missionary, Simon Le Moyne, traveled to central New York in 1654 during a brief truce between the French and the Iroquois (Haudenosaunee) Confederacy.

[5] Great Britain gained full legal control over this territory with the signing of the Treaty of Paris (1763) at the conclusion of the Seven Years' War.

There were very few Catholics settled there, and only a small number of them could make the journey to Albany or New York City to attend mass.

Reverend Paul McQuade, pastor of St. Mary's Church in Albany from 1813 to 1815, frequently visited Utica, and probably celebrated Masses there in private homes.

At the time of Ludden's arrival, the diocese contained 70,000 Catholics, 74 priests, 46 parishes, 20 mission churches, and 16 parochial schools.

[7] In 1909, Reverend John Grimes of Albany was appointed as coadjutor bishop of the diocese by Pope Pius X to assist Ludden.

[7] By the time of Ludden's death in 1912, the diocese had a Catholic population over 150,000, with 129 priests, 80 parishes, 36 mission churches, and 21 parochial schools.

[11] He established a Society for the Propagation of the Faith, 28 parishes, 18 schools, the Loretto Rest facility, and Lourdes Hospital.

In 1933, Monsignor John A. Duffy of the Diocese of Newark was appointed the fourth bishop of Syracuse by Pius XI.

To replace Duffy, Pius IX named Monsignor Walter Foery of the Diocese of Rochester as the next bishop of Syracuse in 1937.

In 1959, he expressed "shock and deep regret" that the Syracuse Metropolitan Health Council had admitted Planned Parenthood.

Cunningham retired six years later and Paul VI named Auxiliary Bishop Francis Harrison of Syracuse to replace him.

Harrison practiced a collegial manner of governing, and worked to include laity and especially women in the diocesan affairs.

[18] In November 2001 he released a pastoral letter to the people of Syracuse entitled: Equipping the Saints for the Work of Ministry.

In a 2011 legal deposition, Bishop Cunningham made statements about the victims of sex abuse describing them as "culpable" and "accomplices".

Bottom line is, I cannot go back and change my words but I can assure you that I did not believe the individual involved in the case was at fault."

[25] In December 2024, priest Nathan Brooks, who once served at parishes in Cortland County, New York, pled guilty to Endangering the Welfare of a Child and was sentenced in Homer Town Court to a term of probation supervision, counseling, and a full stay-away order; Brooks also faced a charge of forcible touching a minor over several years, but the family said it was satisfied with the resolution on the endangering charge.