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What advice would you give to incoming students at Mercer Island High School?
Community prompt from u/allk12. Replies below.
Enrollment
1,439
High
DISTRICT 666 · STATE 573
SCHOOL COMMUNITY·MERCER ISLAND SCHOOL DISTRICT·NCES 530498000761
Mercer Island High School
9100 SE 42nd, Mercer Island, WA 98040 · (206) 236-3345 · King County
GRADES 09–12HIGH21-SUBURBREGULAR SCHOOL1,439 STUDENTS
A+
allk12 Grade
Scored higher than 95% of Washington public high schools
- A+Test scores Share of students meeting the state standard in reading, math, and other tested subjects, 2023-24 and 2024-25.
- A-Beats expectations How far test scores land above or below what the share of low-income students predicts for a school in this state.
- A-Three-year trend Change in reading and math proficiency over the last three test years.
Grades compare a school only with schools in the same state, because every state gives its own test. How grades work · Top-graded Washington public high schools
Student : Teacher
18.8:1
76 FTE teachers
DISTRICT 17.3:1 · STATE 21.6:1
Free / Reduced Lunch
7%
102 students
DISTRICT 6% · STATE 51%
Community
1
0 members
Enrollment and student:teacher ratio compared against other high schools. Free/Reduced Lunch and demographics compared against all schools.
Enrollment by grade, 2024-25
| Grade | Students | Share |
|---|---|---|
| Grade 9 | 352 | 24% |
| Grade 10 | 350 | 24% |
| Grade 11 | 361 | 25% |
| Grade 12 | 376 | 26% |
Student demographics
64%Diversity index
The chance that two students picked at random belong to different racial or ethnic groups.
DISTRICT 66% · STATE 68% · US 70%
Student head counts by race/ethnicity from federal NCES enrollment data. District, state, and US figures are each group's share of all public school students in that area (US excludes territories). Very small groups may be suppressed in the source, so categories do not always sum exactly to total enrollment.
Gender split
School pathway
Feeds from
Based on grade levels within Mercer Island School District. Attendance zones can vary; confirm enrollment with the district.
Test scores
Smarter Balanced + WCAS 2024-25 . % Met or Exceeded StandardEnglish Language Arts
90.7%
WA avg 58.4% . +75.0pp since 2014
Math
76.7%
WA avg 51.2% . +63.7pp since 2014
What this means: On the Smarter Balanced + WCAS, Washington's statewide test, about 91 of every 100 students at this school read and write at grade level and about 77 of 100 do math at grade level. Across all Washington schools, those numbers are about 58 and 51. Reading and writing scores are up about 75 points since 2014, while math scores are up about 64 points.
Smarter Balanced + WCAS results by year
| School year | English Language Arts | Math |
|---|---|---|
| 2024-25 | 90.7% | 76.7% |
| 2023-24 | 82.9% | 75.9% |
| 2022-23 | 82.5% | 71.3% |
| 2021-22 | 86.9% | 75.5% |
| 2018-19 | 91.9% | 83.6% |
| 2017-18 | 88.8% | 79.8% |
| 2016-17 | 44.7% | 21.1% |
| 2015-16 | 51.2% | 47.9% |
| 2014-15 | 15.6% | 12.9% |
% Met or Exceeded Standard, all students and all tested grades.
Source: Smarter Balanced + WCAS. All students, all grades. See all years and grades →
BeatsExpectations
Demographically-adjusted score · methodologyTier
AS EXPECTED
Performing as predicted given the school's student profile
Actual proficiency
76.6%
composite math + reading, all grades
Predicted
75.5%
based on WA schools with similar FRL share
Beats by
+1.2pp
above demographic expectation
What this means: About 77% of students here test proficient in math and reading, compared with the roughly 75% typical for Washington schools with a similar share of low-income students. BeatsExpectations measures results against demographically similar schools rather than by raw scores, and this school falls within the typical range, neither among Washington's top nor bottom 10%.
BeatsExpectations runs a per-state regression of proficiency on free/reduced-lunch share, then scores each school by residual. How this is calculated →
Schools most like Mercer Island High School
Mercer Island High School's state test result (76.6% proficient) is higher than 4 of the 5 schools below with a result.
| School | Students | Low-income | Proficient |
|---|---|---|---|
| Mercer Island High School this school | 1,439 | 7.1% | 76.6% |
| Lake Washington High School Kirkland | 2,081 | 13.5% | 59.2% |
| Liberty Sr High School RENTON | 1,495 | 18.3% | 64.3% |
| Issaquah High School ISSAQUAH | 2,419 | 16.5% | 54.1% |
| Woodinville HS Woodinville | 1,662 | 14.6% | 64.8% |
| Lincoln High School Seattle | 1,770 | 11.6% | 77.6% |
Matched among Washington high schools on enrollment, the share of students from low-income families (eligible for free or reduced-price lunch), and racial and ethnic makeup. Proficient is the average share of students meeting the state standard across all of the school's state tests in 2023-24 and 2024-25, the same combined score our test-score rankings use. Online schools and schools serving specialized populations are not matched.
Where Mercer Island High School ranks
Among high schools| Measure | This school | In Washington | In King County |
|---|---|---|---|
| State test proficiency ranked highest first | 76.6% | #3 of 271 | #2 of 59 |
| Math proficiency ranked highest first | 76.7% | #1 of 321 no change | #1 of 59 no change |
| Reading proficiency ranked highest first | 90.7% | #2 of 327 ▲ 17 | #1 of 61 ▲ 8 |
| 3-year test score change ranked biggest gain first | +2.5pp | #76 of 259 | #13 of 57 |
| Enrollment ranked largest first | 1,439 | #99 of 570 | #34 of 97 |
| Students per teacher ranked fewest first | 18.8:1 | #87 of 311 | #13 of 67 |
| Diversity index ranked most diverse first | 64.0% | #105 of 316 | #50 of 67 |
| Free and reduced lunch ranked highest share first | 7.1% | #381 of 386 | #72 of 76 |
| Enrollment change since 2017-18 ranked steepest decline first | -5.4% | #112 of 164 | #23 of 34 |
Ranked against other public high schools. Online schools are left out of every list, and test-score lists leave out schools that serve specialized populations. Each rank links to the full list. Arrows under a test-score rank show places moved since the prior test year, among schools tested both years.
4-year change
SY 2020-21 vs SY 2024-25Enrollment
1,439
-112 (-7%) vs 2020
+41% since 1990-91, when it was 1,024
Student : Teacher
18.8:1
was 21.0:1
Source: NCES Common Core of Data
Enrollment and staffing by year
| School year | Students | Teachers (FTE) | Students per teacher | Free and reduced lunch |
|---|---|---|---|---|
| 2024-25 | 1,439 | 76.4 | 18.8:1 | 7% (102) |
| 2023-24 | 1,465 | 74.6 | 19.6:1 | 7% (105) |
| 2022-23 | 1,524 | 74.5 | 20.4:1 | 6% (99) |
| 2020-21 | 1,551 | 74 | 21.0:1 | 3% (54) |
| 2017-18 | 1,521 | 75.6 | 20.1:1 | 3% (48) |
| 2015-16 | 1,464 | 72 | 20.3:1 | 4% (58) |
| 2010-11 | 1,432 | 63 | 22.7:1 | 3% (39) |
| 2000-01 | 1,413 | 66 | 21.4:1 | N/A |
| 1990-91 | 1,024 | 46 | 22.3:1 | N/A |
Source: NCES Common Core of Data. Rows are the federal collections on file for Mercer Island High School.
Since 2017-18: students down 5% (1,521 to 1,439); teachers up 1% (75.6 to 76.4).
About Mercer Island High School
Mercer Island High School is a high school located in Mercer Island, Washington, in King County. Federal data show 1,439 students enrolled in grades 9 through 12 in 2024-25. Across high schools in Washington, the average enrollment is about 573.
Mercer Island High School is among 6 schools run by Mercer Island School District, which serves 3,993 students.
The share of White students at Mercer Island High School is 52%, a majority. It is also 25% Asian, 13% multiracial, and 7% Hispanic. Census estimates put King County at about 55% White, close to the school's figure. Its diversity index, the chance that two randomly chosen students belong to different racial or ethnic groups, is 64%.
Teacher count: 76.4 full-time equivalents. Student-to-teacher ratio: 18.8:1. Compared with the 21.6:1 average for high schools in Washington, this school's ratio is lower. Eligibility for free or reduced-price lunch, often used to gauge student poverty, is 7%. Across public schools in King County, the average is 38%.
Mercer Island High School holds an A+ allk12 Grade, placing it above 95% of Washington public high schools.
Test results at Mercer Island High School are 1.2 points above what its free or reduced-price lunch share predicts (76.6% actual, 75.5% predicted).
In the wider King County area, median household income comes to about $124,746, 57% of adults hold a bachelor's degree or higher, and about 5% of residents live below the federal poverty line. King County counts 544 public schools with about 278,492 students.
About 0.2 miles separate Mercer Island High School from the closest public school, Northwood Elementary School. A five-mile radius around the school includes at least 8 other public schools. Ranking the closest schools with test data puts Mercer Island High School at 4th of 9.
Federal records code the school's setting as Suburb: Large.
The 2020-21-to-2024-25 change in enrollment was a 7% decline, from 1,551 to 1,439. The ratio of students to teachers went from 21.0:1 to 18.8:1 over the same years.
This page is set up for the Mercer Island High School community to discuss special education services, counseling, and support programs. Current and former families are welcome to add their experience.
King County at a glance
View full county profilePopulation
2,287,171
Census ACS
Median income
$124,746
Household, ACS
Bachelor's+
57%
Adults 25+
Poverty rate
5%
Below federal line
Schools in county
544
278,492 students
Quick facts
Related schools
Other schools in Mercer Island School District
- Islander Middle SchoolMiddle · 960 students
- West Mercer ElementaryElementary · 431 students
- Lakeridge Elementary SchoolElementary · 401 students
- Northwood Elementary SchoolElementary · 398 students
- Island Park ElementaryElementary · 364 students
Other schools in Mercer Island
- Islander Middle SchoolMiddle · 960 students
- West Mercer ElementaryElementary · 431 students
- Lakeridge Elementary SchoolElementary · 401 students
- Northwood Elementary SchoolElementary · 398 students
- Island Park ElementaryElementary · 364 students
Nearby schools
- Northwood Elementary School0.2 mi · 398
- West Mercer Elementary0.6 mi · 431
- Island Park Elementary1.3 mi · 364
- Enatai Elementary School1.5 mi · 518
- Newport Heights Elementary2.1 mi · 549
- Newport Senior High School2.2 mi · 1,850
Frequently asked questions
About Mercer Island High SchoolWhat is the total enrollment at Mercer Island High School?
Mercer Island High School enrolls approximately 1,439 students in grades 09-12.
Is Mercer Island High School an elementary, middle, or high school?
Mercer Island High School is a high school covering grades 09-12.
How many teachers does Mercer Island High School have?
Mercer Island High School employs 76 FTE teachers, for a student-to-teacher ratio of 18.8:1.
How diverse is Mercer Island High School?
Mercer Island High School reports a student body of 52% White, 7% Hispanic, 1% Black, 25% Asian, 13% Two or more.
Who oversees Mercer Island High School?
Mercer Island High School is overseen by Mercer Island School District in King County.
Data sourceSchool profile facts are sourced from the NCES. Community content is posted by allk12 members.