Holy Trinity Interparochial School, located on First Street, is a Catholic school sponsored by three Roman Catholic parishes, Holy Trinity and St. Helen's in Westfield, and Our Lady of Lourdes in Mountainside.
The Westfield campus houses the 1st—8th grades, with students from two and a half years old to kindergarten attending school on the Mountainside campus. Seventy-five percent of the students are from the parishes in Westfield. According to school data, approximately half of the students are from Westfield, with Scotch Plains being the second largest represented municipality.
Founded in 1916, the school stresses religion as a component in the lives of the students. French and Spanish are taught in the school, along with a technology curriculum. Art, music and physical education are a part of the comprehensive academic curriculum. The school contains a variety of extracurricular activities. Extended day care programs are available for students. Sister Maureen Fichner is the principal.
- Hours: Mon - Fri, 8am - 4pm; Sat, Sun, closed
- Handicap Accessible: Yes
- Number of students: 478
- Male-to-female ratio: 53% female and 47% male
- Public/Private: Private
- Religious affiliation: Roman Catholic
- Accreditation/licenses: Accredited by the Middle States Association
- Parking: Free lot, On-street: free
- Number of faculty: 40
- Grade levels: 1-8
- Special education: Yes
- Features: Auditorium/stage, Cafeteria, Computer lab, Infirmary, Library, Science lab, Sports facilities
- Extracurricular activities available: Student Council, literary magazine, drama club, scouting, choir
- Sports teams: Track, softball, basketball, cross country and cheerleading
- Uniforms: Yes