Ss. Peter and Paul parish was founded in 1830. French missionaries visited the area and celebrated Mass in what is now Beaver in the mid eighteenth century. However, the beginning of the parish can more properly said to have begun with the visit of a priest from St. Patrick, Sugar Creek to celebrate Mass in 1830. For the next few years, the town was regularly visited from either St. Patrick or St. Paul, Pittsburgh (later St. Paul Cathedral). In 1834 land was donated for a church and construction began that year. The finished church was dedicated on June 29, 1837. For the next ten years, the parish was regularly visited from either St. Paul Cathedral or St. Patrick, Pittsburgh.
In 1847, the first resident pastor, Father James Reid, was assigned to the parish. He remained there until his death in 1868. After he died, he was not replaced and Ss. Peter and Paul became a mission of St. Cecilia, Rochester. In 1898 a fire destroyed the church. Land was purchased for a new church and on October 28, 1900, the cornerstone of the church was laid. In that same year, a new resident pastor was assigned to the parish. On December 15, 1901, the new church was dedicated.
On February 22, 1953, ground was broken for a new combination school and church. The church portion was considered a temporary facility that would eventually be replaced by a more permanent structure. The new church and school building was dedicated on April 4, 1954. The old church was converted to a parish hall.
The temporary church served the congregation for almost 20 years. Construction began on the new church in 1971 and the completed building was dedicated on May 29, 1972.
With the turn of the century, trends in the Diocese of Pittsburgh began to reveal a decline in Mass attendance and sacramental participation. At the same time, the number of priests available for parish ministry also began to decline.
To address these challenges, Bishop David Zubik announced on April 12, 2015 a new diocesan initiative, On Mission for The Church Alive!, a consultative strategic planning process designed to foster viable, sustainable and vibrant parishes. As part of this process, the Bishop, in consultation with the faithful, began to consider new models of parish life based on pastoral needs, financial and temporal resources and available clergy.
In 2018, following the period of consultation, parishes were grouped together and served by a single clergy team to eventually form one new parish.
During this transition period, Ss. Peter and Paul Parish remained an independent parish while sharing clergy and staff and eventually publishing a joint bulletin with the other parishes. This ended on January 4, 2021 when Ss. Peter and Paul Parish merged with Holy Family Parish, New Brighton; St. Cecilia Parish, Rochester and St. Felix Parish, Freedom to form the new Our Lady of the Valley Parish. As part of the merger Holy Family Church remained open as part of the new parish.