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Idaho Falls School District 91

Idaho · runs pre-K through grade 12

There is no ZIP Code area where Idaho Falls School District 91 is the only school district serving the homes. It holds a real share in 4 of them and shares every one, with 4 different districts in total. A lookup that returns a single district name for any of those ZIP Codes is guessing which side of a line an address falls on.

It never has a ZIP Code to itself

The counts below come from the census blocks assigned to Idaho Falls School District 91, grouped by the ZIP Code area each block falls in. The Census Bureau publishes the blocks; the grouping is computed here, and it is the only place these particular numbers exist.

  • Homes inside the boundary24,250
  • Residents62,277
  • ZIP Code areas it reaches5
  • Where it is the only district0
  • Where it shares with another district4
  • Where it holds under half a percent1
  • Land area339 square miles
  • Homes per square mile72

The ZIP Code areas it reaches

The spread is the thing to notice. In 83402 this district holds 97% of the homes; in 83444 it holds 2 homes, under half a percent. Same district, opposite answers, and a lookup that names it without the share tells the second household the same thing as the first.

  • ZIP Code 83402 · Idaho Falls, Idaho97% of the homes
  • ZIP Code 83404 · Idaho Falls, Idaho82% of the homes
  • ZIP Code 83401 · Idaho Falls, Idaho33% of the homes
  • ZIP Code 83406 · Ammon, Idaho0.7% of the homes
  • ZIP Code 83444 · Roberts, Idaho2 homes, under half a percent

What one name misses in the areas it leads

Idaho Falls School District 91 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 1,987 of the 20,915 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.

Idaho Falls School District 91 holds 7,984 of the 9,681 homes in ZIP Code 83404 · Idaho Falls, Idaho, so its name is right for most of the area and wrong for the rest: 1,697 homes with Bonneville Joint School District 93 and Shelley Joint School District 60.

In ZIP Code 83402 · Idaho Falls, Idaho the split runs 10,944 to 290 and the larger part is Idaho Falls School District 91's: the rest is 285 homes with Shelley Joint School District 60 and Jefferson County Joint School District 251 and 5 homes in a district too small to name here.

Idaho Falls School District 91 reaches into ZIP Code 83401 · Idaho Falls, Idaho with 5,275 of its 15,922 homes; 3 districts there hold a real share of it, and Bonneville Joint School District 93 leads them. The familiar answer for that area is one of the others, and it is wrong for those 5,275 homes.

Idaho Falls School District 91 is not the name anyone would give for ZIP Code 83406 · Ammon, Idaho — Bonneville Joint School District 93 leads it — and Idaho Falls School District 91 holds 45 homes there all the same. Answer that area with one name and that is what it is wrong about.

Who takes the other homes in its ZIP Codes

Idaho Falls School District 91 runs pre-K through grade 12 itself, so an address it holds sees no change of authority between grade school and high school. The districts listed below are the ones that take the other homes in the ZIP Code areas it shares — Bonneville Joint School District 93, Jefferson County Joint School District 251 and Shelley Joint School District 60. They are neighbors on the same postal ground, not the next stop for its own students.

Who it shares ZIP Codes with

These districts appear alongside Idaho Falls School District 91 in the same ZIP Code areas: Bonneville Joint School District 93, Shelley Joint School District 60, Jefferson County Joint School District 251 and Ririe Joint School District 252. A single-name lookup for one of those areas has to choose between them, and the choice is right for some addresses and wrong for others.

Where this district sits

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 4 of the 5 ZIP Code areas Idaho Falls School District 91 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.