The earliest Catholic settlers in this area had no local services and had to travel to Kingston for their Easter Communion. By 1826, Catholic families were numerous enough to support their own pastor; in 1827, Father James Campion, whose parish extended from Toronto to Windsor, was made pastor. He was succeeded by Father Edward Gordon, who erected churches in a number of communities in his parish, including Our Lady of Peace at Falls View. This church, originally known as St. Edward's Church, was completed on June 13, 1837, and was dedicated to St. Edward, the patron saint of priests. In 1858, the Catholic community in the area had grown so large that St. Edward's was declared a separate parish, and Father Victor Juhel was appointed its first pastor. A frame addition was added to the west end of the structure in 1860, the same year that Archbishop John Joseph Lynch of Toronto purchased 200 acres of land surrounding the church.
On March 1st, 1861, Pope Pius IX decreed the church a place of pilgrimage, and its name was changed from St. Edward's to Our Lady of Peace. In 1875, the Shrine of Our Lady of Peace was placed under the care of the Carmelite Fathers, who were erecting a monastery on an adjacent property. On July 16, 1876, Archbishop Lynch of the Toronto Diocese led a pilgrimage to Our Lady of Peace, and laid the cornerstone for the monastery of Mount Carmel. Stained glass windows, new altars, statues and pews were installed in the church, and a porch was added to the exterior in 1913. In 1950, the church purchased property on Barker Street and converted the Burns Knife Factory (formerly Spence's Carriage Works) and a house beside it, into Mariann Hall, which served as a social activity centre for the church. Mariann Hall acted as a mission church while Our Lady of Peace was renovated and refurbished in 1958. A new Parish Hall opened in 1966, adjacent to the church, on the former site of the Mount Carmel College barn. Our Lady of Peace Church celebrated its sesquicentennial (150th) anniversary in 1987.
St. Patrick's Roman Catholic Church was built at the corner of Victoria Avenue and Maple Street by Father Patrick Mulligan, pastor of Our Lady of Peace, in the early 1860s. In 1863, St. Patrick's was made a separate parish. In 1872, the old church was enlarged to accommodate its growing parish. In October, 1875, pastoral guidance of Our Lady of Peace and St. Patrick's Churches was assumed by the Carmelite Fathers.
Land for the building of a school had been acquired in 1870 from Andrew Menzie, but St. Patrick's school was not built until 1892, by Reverend Domenic Thomas O'Malley. After the school was completed, Father O'Malley began construction of a new church on property which had been acquired from Isaac Beswick in 1885. Ground was broken in early 1895, the cornerstone was laid on June 9, and the new St. Patrick's Church opened on Sunday, December 9, 1895. A rectory was built in the late 1890s, and enlarged in 1924, when a large garage was also added to the church. St. Patrick's Hall, a parish recreational building, was built while Father Fidelis Paulding, O. Carm., was the pastor (1925-1939). In 1966, a new marble altar was installed in the church and the pews were replaced. St. Patrick's Church celebrated its 100th anniversary in 1995, and other than minor changes, the exterior of the building remains essentially the same as when it was built over a century ago.
After World War Two, Niagara Falls and Stamford Township both experienced rapid population growth, and the existing churches realized that new parishes would be necessary to serve this increasing population. On February 4, 1951, St. Patrick's opened a mission named Our Lady of the Scapular in a converted welding shop on Thorold Stone Road near Stamford Centre. Father Wilfred Smith held services in the building until June of 1951, when Father John Austin Sweeney became pastor, and Our Lady of the Scapular became a parish. Father Sweeney's first task was to raise funds to enlarge the existing building. A new church was opened on November 1st, 1960 and blessed by Bishop McCarthy.
Around the turn of the century, the building of power plants attracted a number of Italian immigrants to the area. In 1904, the Reverend Dionysius Best, O. Carm., acquired land on the north-east corner of Lincoln and Seventh Streets (now Forsythe and Buchanan) to build a church to serve the Italian community. Due to financial difficulties, however, the construction of the church was postponed. In 1909, the Reverend Benedict J. O'Neill purchased three lots on the east side of Buchanan Avenue. In 1910, Fathers Anastasio Milani and Telesphor Zazza came to the area from Rome. Father Milani was named the head of the parish, but his ill health caused him to return to Rome in 1911, leaving Father Zazza as his successor.
Father Zazza held his first mass in a private residence on Buchanan Avenue on October 20, 1912, and set to work building a church on Buchanan Avenue. On May 25, 1913, the cornerstone was laid for St. Ann's Church, which was completed by August 10, 1913, and blessed by Archbishop McNeil. In the 1950s, two schools were opened within the parish: St. Joseph's in 1952, and St. Ann's in 1954. In 1955, an adjoining parish residence was built, and the church was completely rebuilt and enlarged in 1957.
On September 21st, 1950, the pastor of the St. Catharine’s Ukrainian Church called a meeting of ten Ukrainian families to consider the possibility of establishing a Ukrainian Catholic parish in Niagara Falls. Father Gregory Boyko came to Niagara Falls in 1951, and began to raise funds to build a Ukrainian Church; in the meantime, he held mass for his Ukrainian congregation on the first Sunday of every month at St. Patrick's Hall. In the spring of 1952, the new pastor, Father Peter Servetnyk, acquired property on Main Street. The ground was broken for a two-storey hall in May, 1952. The cornerstone was laid in August, 1952, and the hall was completed in 1954. Its upper storey served as a chapel.
The parish of St. Thomas More Church was established in 1956, on Dorchester Road. Father Matthew J. Clifford was appointed its first pastor. In October, 1956, a house and property for the church were acquired from the estate of the late Richard Melville Stokes on Dorchester Road, just north of Dunn Street. On February 2, 1958, ground was broken for the church, and Father Clifford offered the first Mass at midnight on Christmas Eve, 1958. On July 2, 1963, fire destroyed the church as well as the parish offices and rectory, which were under construction. The losses were covered by insurance, and the church was rebuilt on the same location by March, 1964.
In 1956, it was estimated that there were 500 French-speaking families in the area. In March of that year, a decision was made to build a church to serve their needs. This church was named for the patron saint of the Franciscan Order, St. Anthony of Padua. Located at 4570 Portage Road, St. Anthony of Padua Roman Catholic Church was officially opened on May 30, 1957, and blessed by His Eminence James Cardinal McGuigan. Classes were begun for parish children in 1957, in the basement of the church, and on August 20, 1958, the Separate School Board purchased three acres of land from the church to establish a bilingual Catholic School.