The church was organized in 1894 by a group of 9 young Swedish immigrants.  Originally known as the Swedish Bethany Congregational Church (the name was changed in 1950), it was built in the same general area as Salem Lutheran Church due to the high concentration of Swedish immigrants that came to work for the Tuttle & Whittemore Malleable Iron Company.

The original church was erected in 1899 but later remodeled into a colonial style with its central spire.  Pews from the old Congregational Church on the Green were acquired when that church was demolished.  The centennial celebration book for the church notes that in its early survival was thanks, in part, to the Congregational Church.  In 1923, Gertrude Whittemore purchased an organ (with her own money) and donated to the church.

Many famous Naugatuckians were part of Hillside’s congregation.  Mr. Dana Blackwell was one of them.  Mr. Blackwell is a former Naugatuck Historical Society President.  He left behind a legacy of passion for the borough’s history, as well as, an enormous wealth of writings and research on the topic.  Mr. Blackwell’s funeral was held at the church on June 20th 2007.

Earl Lindgren, architect and current NHS member, was also a member of the church.  Lindgren was responsible for a contemporary restoration of the church.  He has cited this project as “the most interesting church project’ of his career.  The restoration included removal of the entire roof, stabilizing the exterior walls and reinstalling the roof.