Established in the 18th century
First church around 1850
First priest in 1866

The history of this parish encompasses the Catholic history of all of Albert County. However, it was the Acadians who inhabited these lands before their deportation in 1755.
Irish immigrants arrived in the early 19th century. One of them, Edward O’Donnell, was the first to settle here and thus the first colonist of New Ireland.
Several others followed and established themselves in the community. In the early days, the settlers went to Saint John to receive the sacraments. Later, Father Vericher came to celebrate Mass at the home of Lawrence O’Ragen in Saw Mill Creek. He also visited Hopewell Cape.
After him, Father Ferdinand Gauvreau of Memramcook occasionally ministered at James McArdles's home. Father Gauvreau began the construction of the first church.
Father O'Ragen, who resided in Ward's Creek, Sussex, and served the scattered Irish missions, completed the construction of St. Agatha's Church in New Ireland around 1850. Tradition holds that at that time there was also a temporary chapel built near the present-day Riverside Cemetery; later, this structure was moved to the center of the village and became the Sacred Heart Hall. It was subsequently named St. Catherine's Hall.
From 1866 to 1868, Father David O'Brien was assigned as the first resident priest. He lived in the vestry until he built a residence called Mission House.
A larger church was built in New Ireland, across the road from the old one, and St. Aloysius Chapel was built at Livingston Hill in Albert Mines. After the mines closed in 1918, the church was abandoned, but the cemetery remains.
Father Edward J. McAulay opened St. Isidore Agricola Mission and built a church at Mechanic Settlement in South Branch. When most of the people had left, Father M. F. Lockary abandoned this church. But five years later, in 1912, he had Precious Blood Church built in Goshen. It still exists, but Mass is rarely celebrated there.
In 1890, Father Carson built Sacred Heart Church in Beaverbrook for the parishioners of Riverside, Albert, Harvey, Germantown, Alma, and Hastings.
Around 1892, Father McAulay had a new rectory built. It was there that his housekeeper was murdered in August 1906. Thomas Collins was hanged for this crime. Father McAulay died in 1907 and was succeeded by Francis Lockary, who lived in Sussex. He was the one who had Holy Ghost Church and the rectory built in Riverside. He closed the church in Beaverbrook and served in St. Agatha's, New Ireland, until it was abandoned.
Riverview began serving Riverside in 1959. The rectory was sold, as was the small Sacred Heart Mission in Surry, near Hillsborough. The parish was finally separated from Riverview in 1979.