The Diocese of St. Petersburg comprises 3,177 square miles (8,230 km2), encompassing Pinellas, Hillsborough, Pasco, Hernando, and Citrus counties.

[2] In 1539, Spanish explorer Hernando De Soto, hoping to find gold in Florida, landed near present-day Port Charlotte or San Carlos Bay.

The Spanish missionary Reverend Luis de Cáncer arrived by sea with several Dominican priests in present-day Bradenton in 1549.

Encountering a seemingly peaceful party of Tocobaga clan members, they decided to travel on to Tampa Bay.

Several of the priests went overland with the Tocobaga while Cáncer and the rest of the party sailed to Tampa Bay to meet them.

[4] Arriving at Tampa Bay, Cáncer learned, while still on his ship, that the Tocobaga had murdered the priests in the overland party.

[5] After the end of the French and Indian War in 1763, Spain ceded all of Florida to Great Britain for the return of Cuba.

Given the antagonism of Protestant Great Britain to Catholicism, the majority of the Catholic population in Florida fled to Cuba.

[12] Arizona jurist Edmund F. Dunne established the Catholic colony of San Antonio in Pasco County in the early 1880s.

[13] A contingent of Benedictine monks arrived in San Antonio, Florida, in 1886 initially to serve German immigrants.

Bishop John Moore then invited the Society of Jesus in New Orleans to assume control of the parishes in southern and central Florida.

[2] In 1889, Bishop John Moore asked the Benedictines to establish several mission churches on the Florida Gulf Coast from Pasco County northward.

[17]After World War II, Bishop Joseph P. Hurley of St. Augustine started a massive program of purchasing property throughout Florida to develop new parishes for the increasing Catholic population.

[5] Monsignor W. Thomas Larkin, the vicar general of the diocese and interim diocesan administrator, was appointed the second bishop of St. Petersburg by Pope John Paul II in 1979.

Later that year, he gave support to the Lay Pastoral Ministry Institute, a formal training program for the laity.

With this funding, Lynch opened Bishop McLaughlin Catholic High School in Spring Hill in 2003 and the Bethany Retreat Center in Lutz in 2007.

[2] After Lynch retired in 2016, Pope Francis that same year appointed Bishop Gregory Parkes of the Diocese of Pensacola-Tallahassee as his replacement.

[25] Reverend Robert L. Schaeufele was arrested in Michigan in June 2002 on capital sexual battery charges from Pinellas County in Florida.

[27] Four of Schaeufele's victims sued the diocese in November 2003, claiming that it allowed him access to young children despite previous complaints about his behavior.

[32] In 2011, Lynch published a letter detailing how the diocese had spent $4.7 million since 1990 to settle sexual misconduct cases.

[33][34] In October 2018, Mark Cattell, a magistrate in Virginia, sued the diocese, claiming that he had been sexually assaulted by Reverend Robert D. Huneke from Christ the King Parish in Tampa.