PORTLAND, Ore. — Niche.com's latest ranking of Oregon's top K-12 private schools features a cross-section of institutions that should make state education proponents proud.

While the majority of the top 23 schools — we limited our list to those receiving actual letter grades from Niche, the Pittsburgh-based researcher that crafted the current ratings — are in the Portland region, a healthy complement comes from outside the metro area.

The list includes four schools from Eastern or Southern Oregon, four located in the Willamette Valley and two from central Oregon. Nine of the schools are located in Portland's suburbs while another four are within the city limits.

SEE SLIDESHOW: 2019 Best Private K-12 Schools in Oregon

Niche bases its rankings on several factors using data from the U.S. Department of Education, Niche users and surveys among parents and students, as well as the schools themselves.

SAT/ACT scores supply 30 percent of the overall rating while the "colleges students are most interested in or go on to attend" counts for 25 percent. The rest of the ranking is culled from a compilation of students who go on to four-year colleges (15 percent), culture and diversity (10 percent), surveys on overall experiences (10 percent) and student-teacher ratios (10 percent).

No Oregon schools made Niche's national top private schools list.

Four of the schools on the Oregon list did receive A-plus grades while another three received A's.

Click through on the slideshow link above to learn where your favored private school ranks alongside the state's private institutions.