County averages are 508 on verbal and 519 on math, while state averages are 507 on verbal and 509 on math. National averages are 505 on verbal and 514 on math.
St. Maria Goretti averaged 564 on the verbal portion and 592 on math, with 48 out of 50 seniors taking the test.
Dennis Hoffman, administrator at Grace Academy, said scores are higher at Grace Academy than the county, state and national averages because of the school's disciplined environment and rigorous instruction.
"It's the benefit and quality of a private school Christian education," Hoffman said.
The two seniors who took the SAT at Broadfording Christian Academy averaged 555 on verbal and 540 on math. Broadfording had eight seniors last year.
The eleven seniors out of 20 who took the test at Grace Academy averaged 578 on verbal and 556 on math.
All seven seniors at Heritage Academy last year took the test and averaged 540 on verbal and 510 on math. The math average is nine points lower than the county's.
Highland View Academy seniors averaged 515 on verbal and 483 on math, 36 points lower than the county math average. Thirty-six of the school's 39 seniors took the SAT.
The averages for the county's homeschooled students were not available.
The Washington County Board of Education said a comparison between public and private school SAT scores may not be fair because more public school students take the test than private school students. The School Board has an ongoing goal to increase the number of students who take the test to give more students the option of going to college.
Of the 1,127 public school seniors enrolled last year, 596, or 53 percent, took SATs.
"As we increase the number of students taking the exam, we draw closer to the average student," said Community Relations Specialist Donna Messina. "In the 60's only the very top academic students were encouraged to take the college entrance exams. We now prepare and encourage all students to participate so that the door to higher education is open for every boy and girl in Washington County Public Schools."
The public school averages were also based on students' most recent scores, while the private schools could have taken the best scores and averaged them together. For example, if a public school student took the test last November and again in March, even if the November score was higher, the March score would be used for the averages because it was more recent, according to the School Board.
Chris Hughes, director of guidance at St. James, said because St. James is a college preparatory school, all of the students who enroll plan to go to college, unlike some public school students.
Hughes said students are prepped beginning in the early grades and attend smaller classes than the public schoolers. He also said students can prepare for the SAT by taking review courses and practice tests.
The format for the SAT includes an emphasis on mathematical applications and data interpretation and on critical reading and assessing vocabulary in context.