Published 2026-10-19 · Data: 2020 Census via Geocorr 2022 · Method · Download CSV
Key findings
Families looking for a home are routinely told to search for a school district by ZIP code. Real estate listings, school search filters and many lookup tools do exactly that. But ZIP codes were drawn to deliver mail, and school district lines were drawn separately, often generations earlier. The two rarely match.
We measured how often they disagree using 2020 Census population counted block by block. In 11,330 of the 33,631 populated ZIP code areas in the United States and Puerto Rico, a second school district holds at least 5% of the residents. Across the country, 34.1 million people — about one in ten — live in a different district from the one most of their ZIP code is in. Any tool that answers with one district per ZIP code gives every one of them the wrong answer.
In 660 ZIP codes no single district holds even half of the residents, so there is no “main” district to name at all.
Where ZIP codes are least reliable
The share of residents living outside their ZIP code's main district varies more than twentyfold between states. In Ohio it is 21.1%, about 2.5 million people. In states where a single district covers a whole county, or the whole state, the problem nearly disappears — Hawaii and the District of Columbia each have a single district for everyone.
The largest ZIP codes with no clear district
These are the most populous ZIP codes where the leading district holds less than 60% of residents. In each, a ZIP-code search is close to a coin toss.
| ZIP | Place | Residents | Share of residents by district |
|---|---|---|---|
| 77449 | Katy, TX | 128,180 | Cypress-Fairbanks Independent School District 53%; Katy Independent School District 47% |
| 77084 | Houston, TX | 109,808 | Cypress-Fairbanks Independent School District 58%; Katy Independent School District 42% |
| 75052 | Grand Prairie, TX | 96,225 | Grand Prairie Independent School District 59%; Arlington Independent School District 31%; Mansfield Independent School District 10% |
| 90201 | Bell Gardens, CA | 95,810 | Los Angeles Unified School District 59%; Montebello Unified School District 40%; Downey Unified School District 1% |
| 77584 | Pearland, TX | 93,062 | Pearland Independent School District 57%; Alvin Independent School District 37%; Fort Bend Independent School District 6% |
| 92503 | Riverside, CA | 90,011 | Alvord Unified School District 58%; Riverside Unified School District 42% |
| 78130 | New Braunfels, TX | 88,349 | New Braunfels Independent School District 55%; Comal Independent School District 43%; Seguin Independent School District 2% |
| 93307 | Bakersfield, CA | 88,338 | Greenfield Union School District 42%; Bakersfield City School District 37%; Fairfax Elementary School District 17%; Lamont Elementary School District 2% |
| 92804 | Anaheim, CA | 86,127 | Magnolia Elementary School District 46%; Anaheim Elementary School District 23%; Savanna Elementary School District 17%; Centralia Elementary School District 11% |
| 92154 | San Diego, CA | 84,027 | South Bay Union School District 51%; Chula Vista Elementary School District 29%; San Ysidro Elementary School District 20% |
| 73099 | Yukon, OK | 83,213 | Yukon Public Schools 56%; Mustang Public Schools 37%; Piedmont Public Schools 5%; Banner Public School 2% |
| 93727 | Fresno, CA | 83,212 | Fresno Unified School District 48%; Clovis Unified School District 31%; Sanger Unified School District 20% |
The most divided ZIP codes
Some ZIP codes cross so many lines that no single answer is useful. These have the most districts that each hold at least 5% of residents.
| ZIP | State | Districts | Share of residents by district |
|---|---|---|---|
| 44481 | Ohio | 7 | Lordstown Local School District 32%; Champion Local School District 28%; Newton Falls Exempted Village School District 9%; LaBrae Local School District 8%; Lakeview Local School District 7%; Warren City School District 6%; Weathersfield Local School District 6% |
| 60411 | Illinois | 6 | Chicago Heights School District 170 41%; Community Consolidated School District 168 18%; Sunnybrook School District 171 11%; Flossmoor School District 161 8%; Sandridge School District 172 7%; Steger School District 194 5% |
| 49201 | Michigan | 6 | Northwest School District 37%; Jackson Public Schools 24%; Napoleon Community Schools 12%; East Jackson Community Schools 8%; Michigan Center School District 7%; Western School District 6% |
| 60441 | Illinois | 6 | Homer Community Consolidated School District 33C 28%; Will County School District 92 25%; Lockport School District 91 17%; Fairmont School District 89 10%; Taft School District 90 9%; Chaney-Monge School District 88 8% |
| 07840 | New Jersey | 6 | Hackettstown Town School District 33%; Mansfield Township School District 17%; Allamuchy Township School District 14%; Great Meadows Regional School District 14%; Washington Township School District 12%; Mount Olive Township School District 10% |
| 60527 | Illinois | 6 | Gower School District 62 34%; Community Consolidated School District 180 22%; Maercker School District 60 16%; Pleasantdale School District 107 12%; Hinsdale Community Consolidated School District 181 8%; Cass School District 63 7% |
Two districts at one address
A separate issue stacks on top of this one. In parts of Illinois, California, Arizona, New Jersey, Montana and several other states, one district runs the elementary schools and a different district runs the high school. 22.3 million people (6.66% of residents) live in areas like that, so the honest answer to “which district am I in?” is two districts, depending on the child's grade. How split elementary and high school districts work.
What this means if you are moving
A ZIP code is a reasonable first filter, but it is not an answer. Before you sign a lease or make an offer:
- Search the street address, not the ZIP code. Our address lookup matches the location to official NCES district boundaries and lists every district that serves it.
- Confirm with the district. Districts publish their own school locators and registrars answer this question every day. Ask about the exact address, because a boundary can split a street by house number.
- Do not rely on a listing's school field. Listings often fill it from the ZIP code or the mailing city, which is how a home ends up advertised with a district it is not in.
We had this problem too
This analysis started as an audit of our own pages. Like most lookup sites, SchoolDistrictFinder publishes one page per ZIP code, and some of those pages named a district that serves only a small corner of the ZIP code. In October 2026 we checked every page against the population data behind this study and corrected the district on more than 700 of them. Where a ZIP code is genuinely shared, its page now lists every district and its share of residents. If you find a page that is still wrong, tell us.
Method
Source. Geocorr 2022 from the Missouri Census Data Center, which allocates 2020 Census block population between ZIP Code Tabulation Areas (ZCTAs) and 2020 Census school district boundaries. ZCTAs are the Census Bureau's area approximations of ZIP codes; a few ZIP codes used only for post office boxes or single buildings have no ZCTA.
Definitions. Each resident is assigned to the district that serves them in the lower grades: their unified district, or their elementary district where elementary and secondary districts are separate. A ZIP code's main district is the one holding the most residents. Residents outside it are everyone else in the ZIP code. A ZIP code is split when a second district holds at least 5% of its residents; at 1% the count is 16,159, at 10% it is 8,132, and at 25% it is 3,483. Two-district residents are those in areas with a separate secondary district.
Coverage. 33,631 populated ZCTAs and 334.7 million residents in the 50 states, the District of Columbia and Puerto Rico. Puerto Rico, Hawaii and the District of Columbia each have a single district, so nobody there lives outside it. Each ZIP code is counted in the state where most of its residents live.
Limits. Boundaries are as of 2020. Districts that have merged or redrawn their lines since then are shown as they were, and district names are the Census names from that year. The figures describe where people live, not where children attend school: transfers, charter schools and open enrollment are not counted.
Data and citation. The full table, one row per ZIP code, is free to use under CC BY 4.0: zip-district-splits.csv. Please cite: SchoolDistrictFinder.us analysis of 2020 Census population by ZIP Code Tabulation Area and school district (Geocorr 2022, Missouri Census Data Center), with a link to this page. Journalists can reach us through the press page.
Frequently Asked Questions
How many Americans live outside their ZIP code's main school district?
About 34.1 million people, or 10.19% of residents, according to 2020 Census population by ZIP Code Tabulation Area and school district. A lookup that assigns one district per ZIP code gives all of them the wrong district.
How many ZIP codes are split between school districts?
11,330 of 33,631 populated ZIP code areas (33.7%) have a second district holding at least 5% of their residents. 3,021 are split three or more ways, and 660 have no district with a majority.
Which state has the most residents outside their ZIP code's district?
Ohio: 21.1% of residents, about 2.5 million people, live outside their ZIP code's main district.
How do I find my school district if my ZIP code is split?
Search by street address rather than ZIP code. The address is matched to official NCES school district boundaries, which returns every district that serves that location. Then confirm with the district before enrolling or buying a home.