#1 Fastest-Growing Private Schools in Union County, NJ
Cornerstone Day School
Special education school · Grades 6–12
Enrollment up 92% in about a decade
Cranford, NJ
B+Overall grade125 students7 students per teacher
2026 lists
Fastest-Growing Private Schools in Union County, NJ
Private schools in Union County, NJ whose enrollment has grown the most over the past decade. Top 5 of 5 schools.
#2 Fastest-Growing Private Schools in Union County, NJ
PNS&K
Early childhood program · Grades Pre-K–K
Enrollment up 92% in about a decade
Westfield, NJ
B+Overall grade69 students8 students per teacher
#3 Fastest-Growing Private Schools in Union County, NJ
First Children School
Special education school · Grades Pre-K–12
Enrollment up 73% in about a decade
Plainfield, NJ
A+Overall grade78 students5 students per teacher
#4 Fastest-Growing Private Schools in Union County, NJ
Newmark High School
Special education school · Grades 1–8
Enrollment up 71% in about a decade
Scotch Plains, NJ
B+Overall grade96 students7 students per teacher
#5 Fastest-Growing Private Schools in Union County, NJ
Holy Trinity
Diocesan school · Grades Pre-K–8
Enrollment up 11% in about a decade
Westfield, NJ
AOverall grade303 students12 students per teacher
From official public records, updated October 2026.