Several years ago, Sacred Heart Parish and St. Dominic Parish became one under the new twinning program in the diocese, sharing resources and staff where it was desired. Eventually they became one parish, located in Sacred Heart Church, serving the West End, Park Street, and Hispanic communities of Portland.

The history of each of these parishes is unique, yet in many ways, similar. Both recognized that the hundreds of Irish Catholic immigrants looking for a better life in America needed a church to unite them in this unfamiliar land. Both petitioned the Diocesan Bishops for aid and both were strongly supported from the time of their requests. Bishop Benedict J. Fenwick, after a visit to Portland Catholics in 1827, kept his promise to send a priest to start a parish in the city. Father Charles Daniel French proved to be an excellent choice, a strong leader who was able to administer the parish as well as raise money (even from many non-Catholics) for their church. After a year of devoted effort the foundation stone was laid on the corner lot on State Street, June 13, 1828. St. Dominic Church became the first Catholic Church in Portland.

The population of the parish grew steadily from the original 200 to 2000 by 1860. By 1887 the need for a new and larger church was a proven necessity with almost 4000 parishioners. Bishop James Healy approved their petition and the corner stone for the present St. Dominic Church was laid on August 10, 1888. St. Dominic Parish celebrated the 100th Anniversary of its founding on October 9, 1930 and the 150th Anniversary on November 2, 1980.

Sacred Heart Parish followed a like pattern, first recognizing the need, then petitioning the Bishop. Bishop James Healy, in May of 1896, sent Father John O'Dowd to establish the parish and build the church. Father wasted no time using the local paper, The Argus, to publicize his plans for the church and raising money by visiting every Catholic family in Portland, including those of St. Dominic Parish. Ground was broken in July on the corner lot of Mellen and Sherman Streets; the cornerstone was laid November 15, 1896; and the first Mass was celebrated on April 11, 1897. A beautiful chapel in the basement served until the main church could be completed. The growth of the parish was continuous and grateful parishioners filled the new Church of the Sacred Heart for the first Mass, July 4, 1915. Sacred Heart became the third parish in Portland, the Cathedral of the Immaculate Conception having been founded in 1875. Sacred Heart Parish celebrated its 100th Anniversary in June 1996.

Both churches have been nominated to the National Registry of Historic Places.