Each score is graded separately against Maryland schools. A school can be strong at moving students forward (growth) without having the highest test scores, or the reverse. How we score schools
What Goes Into This Rating
| Factor | Weight | Score | Basis |
|---|---|---|---|
| 📚 Academics (reading & math) | 55% | 47/100 | reading 42nd percentile, math 52nd percentile among Maryland high schools (2018–19 state tests) |
| 🎓 Graduation (4-year, diploma only) | 25% | 71/100 | 92% graduate on time with a regular diploma |
| 🏫 Resources (class size, funding, size, type) | 20% | 75/100 | Inputs from NCES school and district data |
Students served: 44% students directly certified for free meals (their families receive SNAP or similar aid). Compared with Maryland schools serving a similar share of low-income students, this school’s reading and math results are −3 points worse than expected. (Context only; not part of the score.)
The overall Repit Score ranks this blend against every rated school in Maryland. Schools are compared within their state because each state sets its own tests and proficiency bar. How we rate schools
Test Scores & Graduation
| 📖 Reading proficiency | 50% (+6 pts vs. state avg 44%) Students scoring proficient on the state test, 2018–19 |
| ➗ Math proficiency | 39% (+2 pts vs. state avg 37%) Students scoring proficient on the state test, 2018–19 |
| 🎓 Graduation rate | 92% (+11 pts vs. state avg 81%) Four-year adjusted cohort graduation rate, class of 2020 |
Source: U.S. Department of Education EDFacts via the Urban Institute Education Data Portal. Federal reporting rounds small schools to ranges; we show the midpoint. Proficiency standards differ by state, so compare schools within the same state.
How Student Groups Do Here
Share of each group of students scoring proficient on the Maryland state test (2018–19), compared with the same group of students across the state. Differences between groups are shown as reported; they reflect many factors inside and outside school.
| Students | Reading | Math | vs. same group statewide | Rank in state for this group |
|---|---|---|---|---|
| White | 57% | 52% | reading -18 pts, math -11 pts | 21st percentile (list) |
| Black | 37% | 22% | reading -3 pts, math -2 pts | 42nd percentile (list) |
| Hispanic | 35% | 25% | reading -9 pts, math -2 pts | 28th percentile (list) |
| Asian | 75% | 65% | reading -7 pts, math -15 pts | 23rd percentile (list) |
| Multiracial | 70% | 35% | reading -2 pts, math -25 pts | 24th percentile (list) |
| Low-income | 37% | 22% | reading -2 pts, math -1 pts | 38th percentile (list) |
Source: U.S. Department of Education EDFacts via the Urban Institute. Groups with fewer than 20 tested students are not shown. Results are achievement (proficiency), not growth; growth by group is not published for individual schools.
School Information
| Address | 600 Patriot Ln |
| City | Millersville |
| ZIP Code | 21108 |
| District | 2400060 |
| NCES School ID | 240006000109 |
| Data Year | 2024-25 |
Community Context for 21108
Understanding the community around Old Mill High helps evaluate the school environment and neighborhood.
💰 Income & Economy
| Median Household Income | $142,001 |
| Per Capita Income | $57,453 |
| Poverty Rate | 2.4% |
| Households Earning $100K+ | 67.1% |
🎓 Education Level
| Bachelor's Degree or Higher | 49.9% |
| High School or Higher | 96.5% |
🏠 Housing
| Median Home Value | $527,700 |
| Median Rent | $1,886 |
| Owner-Occupied | 88.6% |
| Renter-Occupied | 11.4% |
Thinking about moving into this school’s area? See what homes and rents actually cost in ZIP 21108 — values, rent, and how it compares to nearby ZIPs. Free, no signup. See 21108 housing costs →
Student Demographics
Enrollment and demographic breakdown for Old Mill High.
👫 Gender Distribution
🌎 Race & Ethnicity
📋 Enrollment Summary
| Total Enrollment | 2,489 |
| Teachers (FTE) | 145.0 |
| Student:Teacher Ratio | 17.2:1 |
Frequently Asked Questions
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Other Schools in 21108
About Repit School Scores
Parents choosing a school deserve to see what it actually delivers. Since October 2026 the Repit School Score is built mainly on results:
- Academics (largest share) — the share of students scoring proficient in reading and math on the state test, ranked against schools of the same level in the same state.
- Graduation (high schools) — the four-year adjusted cohort graduation rate. Only regular diplomas count; GEDs and certificates of attendance do not.
- Resources (smaller share) — class size, per-pupil funding, school size and type.
Scores compare schools within their own state, because every state writes its own tests and sets its own proficiency bar. Full methodology
Data sources: NCES CCD 2024-25, U.S. Dept. of Education EDFacts (test results & graduation) | Last updated: October 2026