Alhambra Unified School District (9-12)

It never has a ZIP Code to itself

At 3,325 homes to the square mile this is city territory, and district lines in a city follow streets. Alhambra Unified School District (9-12) covers 5 square miles in all — small enough that a single ZIP Code area can hold most of it, and several ZIP Codes can cut across it.

• Homes inside the boundary15,224
• Residents51,036
• ZIP Code areas it reaches4
• Where it is the only district0
• Where it shares with another district3
• Where it holds under half a percent1
• Land area5 square miles
• Homes per square mile3,325

The ZIP Code areas it reaches

Every one of the 3 areas where it holds a real share it shares with somebody. Its largest foothold is 91770 at 52% of the homes; the thinnest is 91733, where it holds no homes at all.

• ZIP Code 91770 · Rosemead, California52% of the homes
• ZIP Code 91755 · Monterey Park, California48% of the homes
• ZIP Code 91776 · San Gabriel, California14% of the homes
• ZIP Code 91733 · South El Monte, Californiano homes at all

The areas it leads without holding most of the homes

Alhambra Unified School District (9-12) is the largest district in 2 ZIP Code areas, and not one of them is wholly its own. Answer with its name alone and the answer misses 13,288 of the 26,708 homes those areas hold. That count is computed here from census blocks; the lookups that answer this question with a single name never print it.

Alhambra Unified School District (9-12) holds 8,969 of the 17,412 homes in ZIP Code 91770 · Rosemead, California, so its name is right for most of the area and wrong for the rest: 8,417 homes with El Monte Union High and Montebello Unified and 26 homes in a district too small to name here.

Alhambra Unified School District (9-12) is the largest name in ZIP Code 91755 · Monterey Park, California and still holds a minority of it: 4,451 of 9,296 homes. The other 4,845 homes are with Alhambra Unified School District and Montebello Unified. This is the shape that makes a one-name answer worst — the name is right for fewer homes than it is wrong for.

In ZIP Code 91776 · San Gabriel, California this district is one name among 5. San Gabriel Unified leads with the largest share and Alhambra Unified School District (9-12) holds 1,804 of the 12,674 homes counted there; no single name describes that area at all.

The elementary districts that feed it

Students arrive at Alhambra Unified School District (9-12) from 5 districts that run the lower grades on the same ground — Garvey Elementary, which sends 46%, Rosemead Elementary, which sends 22% and Montebello Unified, which sends 12%. Each of those addresses therefore belongs to two districts at once, one for grade school and this one for high school, and neither name is the whole answer.

• Garvey Elementary School District46% of Alhambra Unified School District (9-12)'s homes come from here
• Rosemead Elementary School District22% of Alhambra Unified School District (9-12)'s homes come from here
• Montebello Unified School District12% of Alhambra Unified School District (9-12)'s homes come from here
• Alhambra Unified School District10% of Alhambra Unified School District (9-12)'s homes come from here
• San Gabriel Unified School District9.4% of Alhambra Unified School District (9-12)'s homes come from here

The names in this list are exact: the federal file gives the district of each band for every census block. The percentages are not. They spread each shared ZIP Code area's homes across the other band in proportion to the share each district holds there, because the file names the two districts of a block and not how a household moves between them. Read them as the size of the crossing, not as a count of houses.

Who it shares ZIP Codes with

Alhambra Unified School District (9-12) shares ZIP Code areas with 6 different districts. The most frequent are Garvey Elementary, El Monte Union High, Montebello Unified and Rosemead Elementary. In a neighborhood this crowded the question is not which district serves the ZIP Code but which side of which street an address is on.

• Garvey Elementary School District3 shared ZIP areas
• El Monte Union High School District2 shared ZIP areas
• Montebello Unified School District2 shared ZIP areas
• Rosemead Elementary School District2 shared ZIP areas
• Alhambra Unified School District1 shared ZIP area
• San Gabriel Unified School District1 shared ZIP area

Where this district sits

• School districts in California996 of 1,788 ZIP areas split
• Every district with a page here260 districts listed

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: in 3 of the 4 ZIP Code areas Alhambra Unified School District (9-12) reaches, at least one other district holds a real share of the homes as well, and the line between 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.