ZIP Code Territory Map
Split one or more states into territories made of whole ZIP codes. Type your bases or ask for a number of territories, balance them by population or by ZIP count, then move any ZIP code by hand. Every ZIP code area goes to exactly one territory, territories stay in one piece, and if a fair split isn't possible the tool says so. Export the result as a CSV of ZIP codes, or as territory outlines in GeoJSON or KML.
Free Sales Territory Map by ZIP Code
Choose a state, or a state and its neighbours, and this tool divides every ZIP code area in it between your territories. Give it your own bases (offices, depots, reps' home ZIP codes) or a number of territories, and it builds them from whole ZIP codes: each ZIP code goes to its nearest base first, then ZIP codes along the borders are passed between neighbouring territories until the territories hold about the same population, or the same number of ZIP codes.
It is meant for sales territories, delivery zones, franchise areas, field service and inspection patches, or any job where a list of ZIP codes needs to be split fairly between people.
How the Territories Are Built
- Real ZIP code shapes. Territories are drawn from the Census Bureau's ZIP code areas themselves, not from circles or cells around a point. In rural states a ZIP code area can be larger than a county, and a cell around its centre would miss a third or more of it (measured on Nevada, Wyoming, Montana and Texas).
- Neighbours share a border. Two ZIP codes count as neighbours only when their areas share a stretch of border. A territory grows or shrinks only across those borders, so it stays in one piece.
- Gap links, shown. Islands and shores across water touch nothing, so each is joined to its nearest ZIP code by a dashed line on the map and listed under the territories. This is a straight-line join, not a road or a ferry.
- Balanced along chains. A territory that only borders territories already at their share can still grow: they pass ZIP codes on from the territories that have too many.
- Honest about limits. If a territory cannot reach its share (a base in a thinly populated corner, say), the table shows how far off it is.
Data Sources
ZIP code areas: U.S. Census Bureau, 2020 ZIP Code Tabulation Areas, cartographic boundary file (1:500,000), simplified for the web as one shared set of borders. State outlines: U.S. Census Bureau 2020 cartographic boundaries. Population: U.S. Census Bureau, American Community Survey 2020-2024 5-year estimates, by ZIP Code Tabulation Area. Each ZIP code area's centre is the Census Gazetteer's internal point. All public domain. Base ZIP codes and city names: the SimpleMaps US ZIP Code Database (Basic). Map tiles: OpenStreetMap contributors.
Frequently Asked Questions
How do I create a territory map with ZIP codes?
Pick a state (and any neighbouring states you cover), then either type your bases, one per line as a ZIP code, an address with a ZIP, or a city, or ask for a number of territories and let the tool place the bases. Choose whether to balance by population or by number of ZIP codes and press Make territories. Every ZIP code area in the chosen states goes to exactly one territory, and you can move any ZIP to another territory by clicking it.
What does balancing by population mean?
Each territory starts with the ZIP codes nearest its base. ZIP codes are then passed between neighbouring territories, one border ZIP at a time, until every territory holds about the same number of people (within 5%), or no further move helps. Population is the Census Bureau's American Community Survey 2020-2024 estimate for each ZIP code area. If a territory cannot reach its share, the tool says so and by how much.
Does every territory stay in one piece?
Yes, as far as the map allows. A ZIP code only moves to a territory it shares a border with, and never if that would split the territory it leaves. Where ZIP code areas do not touch at all, such as islands or shores across a wide bay, the tool joins them to the nearest ZIP code with a dashed gap link and lists each one, so you can see where a territory crosses water or an empty area.
How accurate are the ZIP code boundaries?
They are the Census Bureau's 2020 ZIP Code Tabulation Areas (ZCTAs), which approximate the areas the Postal Service delivers to. They are not official USPS boundaries, and ZIP codes change more often than ZCTAs are redrawn. ZIP codes that only serve PO Boxes or a single organization have no area, so they cannot be part of a territory map, though you can still use one as a base.
Can I export the territories?
Yes. The CSV has one row per ZIP code with its city, state, territory, base, distance to the base and population, and marks ZIP codes you moved by hand. The GeoJSON and KML files have one outline per territory for GIS tools and Google Earth, with the list of ZIP codes in each.
Is the ZIP code territory map free?
Yes, with no sign-up. The territories are worked out in your browser. The map data comes from our own servers, and a base typed as a city or place name is looked up in our own place data. Nothing you type is stored by MapTools.