DistrictByZip Every school district that touches your ZIP Code

School districts in Maryland

16% of the 469 populated ZIP Code areas in Maryland are served by more than one school district — 74 of them, which puts the state 45th among the fifty-two. It is organized into 24 unified districts, the largest being Montgomery County at 404,423 homes. Its most divided ZIP Code area, 21771, is split between 4 districts for elementary grades alone. The two districts that share the most ZIP Codes here are Baltimore County and Baltimore City, in 14 of them. Counted by homes rather than by ZIP Code area, 22% of the state's housing sits in a ZIP Code that more than one district serves.

How often a ZIP Code here crosses a district line

The state sits well below the national rate of 53%. Montgomery County alone covers 404,423 homes, and districts that size swallow whole postal areas rather than splitting them. Where a ZIP Code area here does cross a line, it is worth checking precisely because it is unusual.

  • ZIP Code areas with a district469
  • Served by more than one district74 (16%)
  • Grade school and high school differ0 (0%)
  • No high school district named0
  • Unified districts24
  • Elementary districts0
  • Secondary districts0
  • Homes in no district at all0

The largest districts in Maryland

The top of the list is unusually flat: Montgomery County, Prince George's County and Baltimore County are within a few percent of each other at around 404,423 homes apiece. Where districts are evenly matched, no one of them owns a postal area, and the shares below tend to be split rather than lopsided.

The most divided ZIP Code area in Maryland

ZIP Code area 21771 holds 10,942 homes, and 4 districts each take a meaningful share of them for elementary grades — Frederick County first at 45%, then Carroll County. A lookup that names the first is describing that share of the homes and silently not the 6,058 homes that remain.

Grade schoolFrederick County Public Schools45%4,884 of 10,942 homes
High schoolFrederick County Public Schools45%4,884 of 10,942 homes

Each percentage here is a share of the 10,942 homes counted in ZIP Code 21771, not the chance that any one address is in that district. Enrollment follows the street: two houses on opposite sides of the same road can be in different districts, and only the district office can say which.

Every track below is 35 cells long and stands for all 10,942 homes counted in ZIP Code 21771, so one cell is 313 homes, rounded to the nearest whole cell. Cells lit solid are the homes one district holds, and the unlit cells are the homes held by the other districts in the same list.

  • Frederick County Public Schools4,884 of 10,942 homes45%
  • Carroll County Public Schools4,810 of 10,942 homes44%
  • Howard County Public Schools1,115 of 10,942 homes10%
  • Montgomery County Public Schools133 of 10,942 homes1.2%

For grade school, an answer of one district name would be wrong for 6,058 of the 10,942 here.

Where a single district name still works in Maryland

Across the 469 ZIP Code areas in Maryland with homes in them, an answer of one district name misses 76,354 of the 2,530,673 homes they hold. That is 3.0% of the state, and in 389 of the areas one name covers everything: this is a state where the familiar answer is usually the right one, and the areas below are where it is not.

ZIP Code 21771 · Green Valley, Maryland names 4 districts. Frederick County is the largest of them for grade school, and an answer of its name alone misses 6,058 of the 10,942 homes there; Carroll County, Howard County and Montgomery County hold the rest.

In ZIP Code 21207 · Lochearn, Maryland the largest district for grade school is Baltimore County, and naming it alone misses 6,054 of the 20,214 homes counted there. The rest are with Baltimore City.

In ZIP Code 21225 · Brooklyn Park, Maryland the largest district for grade school is Baltimore City, and naming it alone misses 5,926 of the 13,658 homes counted there. The rest are with Anne Arundel County.

Where a ZIP Code here names more than one district

Of the 469 ZIP Code areas in Maryland that the federal file names a district for, 74 name more than one school district. These are the 12 with the most, starting at 4 districts in one postal area: Green Valley, Eldersburg and Queen Anne. Each row opens the full answer for that ZIP Code, with every district named for grade school and for high school and the share of the homes each one holds.

What to do next

Ask the district office to confirm your street address. A district settles that question on its own site: look for a school locator, a find my school tool, or an attendance zone map. Where there is none, ask the office itself.

A ZIP Code is a set of mail delivery routes, not a boundary: 74 of the 469 ZIP Code areas in Maryland with a district named for them are served by more than one school district, and the line between two of them runs along streets. Only the district can say which side of that line an address is on.

This site links to no district website. None of the federal files it is built from publishes one, and a guessed address is worse than none. It is the district office, not a search engine, that settles an address.

If a house purchase depends on the answer, ask the district itself for written confirmation of that exact address. A listing is not a district record, and neither is this page.

What this cannot tell you

The homes were counted in the 2020 Census and the district lines are the 2026 boundary file. Nothing on this page adjusts one to the other. Where houses have been built or cleared since the count, a share here describes the place as it was counted rather than as it stands today, and in the fastest-growing ZIP Code areas that gap is the largest single source of error on this site.

A share on this page is a share of the homes in the ZIP Code area, not a probability for any particular address. Enrollment is decided by street address, and a district may run magnet, charter or choice programs that ignore the boundary entirely. If a decision depends on the answer, the district office is the only authority; this page shows what the federal boundary files say and when they were published.

A district boundary is not a school attendance zone. This site never says which school an address is assigned to: no current national dataset of attendance zones exists, and the district draws them itself. Nor is anything here endorsed or certified by the Census Bureau; we use their published files, and that is the whole of the relationship.

A ZIP Code is a set of mail delivery routes, not an area. What is mapped here is the Census Bureau's ZIP Code Tabulation Area, the closest published approximation to it. The two are not identical, and a handful of ZIP Codes used only for post office boxes or single buildings have no tabulation area at all.

Where these numbers come from

School district boundaries come from the Census Bureau's Census Geographic Relationship File, current 2026 vintage, which assigns every census block to a unified district or to an elementary and a secondary district. Homes and residents in each block come from the 2020 Census Redistricting Data (PL 94-171), H1_001 and P1_001. The ZIP Code areas come from the same Geographic Relationship File, block to ZIP Code Tabulation Area. District names and grade ranges come from the Census Gazetteer 2025, with 2020 for districts no longer listed.

The place name printed beside a ZIP Code comes from the Census 2020 ZIP Code Tabulation Area relationship files: place, county subdivision and county, taken 2026-09-06. It is a label rather than a measurement: the Census Bureau does not publish which post office a ZIP Code belongs to, so the place named is the one covering the most land inside the area, not the city the Postal Service prints on an envelope.

Everything else on this page — the shares, the counts of districts per ZIP, the comparison between the two grade bands, the rankings — is computed here from those files. The source publishes none of it. Snapshot taken 2026-09-03.