Every state, by how often a ZIP Code crosses a district line

• Montana85% of 368 ZIP Code areas
• Nebraska81% of 583 ZIP Code areas
• Wisconsin77% of 781 ZIP Code areas
• Minnesota77% of 878 ZIP Code areas
• Michigan76% of 987 ZIP Code areas
• North Dakota75% of 386 ZIP Code areas
• Illinois74% of 1,394 ZIP Code areas
• Oklahoma73% of 663 ZIP Code areas
• South Dakota73% of 375 ZIP Code areas
• Missouri72% of 1,034 ZIP Code areas
• Iowa70% of 969 ZIP Code areas
• Kansas68% of 702 ZIP Code areas
• Ohio65% of 1,228 ZIP Code areas
• Indiana64% of 806 ZIP Code areas
• Arizona63% of 409 ZIP Code areas
• Vermont63% of 264 ZIP Code areas
• Texas63% of 1,976 ZIP Code areas
• Arkansas62% of 614 ZIP Code areas
• Mississippi61% of 423 ZIP Code areas
• New York56% of 1,807 ZIP Code areas
• California56% of 1,788 ZIP Code areas
• New Jersey54% of 597 ZIP Code areas
• Tennessee52% of 631 ZIP Code areas
• Georgia52% of 744 ZIP Code areas
• Alabama51% of 648 ZIP Code areas
• Delaware50% of 68 ZIP Code areas
• Washington49% of 600 ZIP Code areas
• Oregon48% of 425 ZIP Code areas
• Pennsylvania48% of 1,826 ZIP Code areas
• Colorado45% of 520 ZIP Code areas
• Idaho43% of 278 ZIP Code areas
• South Carolina42% of 421 ZIP Code areas
• Kentucky39% of 775 ZIP Code areas
• North Carolina38% of 848 ZIP Code areas
• New Hampshire36% of 247 ZIP Code areas
• New Mexico34% of 367 ZIP Code areas
• Virginia33% of 895 ZIP Code areas
• Wyoming31% of 179 ZIP Code areas
• Maine29% of 426 ZIP Code areas
• Connecticut28% of 288 ZIP Code areas
• Massachusetts28% of 534 ZIP Code areas
• Louisiana26% of 535 ZIP Code areas
• Rhode Island23% of 81 ZIP Code areas
• West Virginia23% of 738 ZIP Code areas
• Maryland16% of 469 ZIP Code areas
• Utah14% of 293 ZIP Code areas
• Nevada12% of 177 ZIP Code areas
• Florida11% of 1,006 ZIP Code areas
• Alaska8.2% of 243 ZIP Code areas
• District of Columbia0% of 34 ZIP Code areas
• Hawaii0% of 95 ZIP Code areas
• Puerto Rico0% of 132 ZIP Code areas

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: 17,865 of the 33,555 ZIP Code areas in the country with homes in 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.

Reading the ranking

The list runs from Montana at the top, where 85% of postal areas cross a district line, to Puerto Rico at the bottom. 22 of the 52 jurisdictions sit above the national rate of 53%, and 3 of them are at zero, where one district covers everything and no lookup is needed at all. The middle of the list is where a ZIP Code answer is most misleading, because a reader there has no reason to suspect a second district and often has one.

Two arrangements do most of the work. In 7 states at least one home in twelve sits under an elementary district with a separate secondary district over it, so one address carries two district names at once. And in 21 the file names no high school district for part of the homes — Missouri, Oklahoma and Vermont lead that count with 140, 124 and 116 areas — which is a town running its own grade school and paying another district to take its high school students.

The count of districts is what drives the ranking, and it is visible in the arithmetic: the ten states at the top keep 4,128 school districts over 7,449 populated postal areas, while the ten at the bottom keep 295 over 3,268. A state that runs one district per county has postal areas that sit inside a district; a state that runs one per township has districts that sit inside a postal area, and every boundary between them is a line a lookup cannot see.

Each state page below carries the same figures for that state, the districts inside it that have a page here, and the postal areas where the answer takes the most names — with the town each one is in, so that the row can be recognized rather than decoded.

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.