How Geographically Concentrated Is US Industry? #
Industry geographic concentration is usually discussed at the level of famous clusters — tech on the West Coast, energy in Texas, finance in New York. The federal employment record shows something considerably more extreme underneath those headlines. A substantial number of American industries are not clustered so much as located: they happen in one or two places and effectively nowhere else.
Run every NAICS-classified industry against its state employment distribution and the shape is bimodal. Most industries are spread roughly in line with population, because they serve local demand — restaurants, dentists, plumbers, grocery stores. A minority are concentrated to a degree that has no relationship to population at all, and those are the industries where geography is the single most important fact about the market.
The Industries That Exist in Only One State #
At the extreme end, a single state accounts for more than 90% of national employment in five US industries. In two of them, the federal record shows no measured employment outside one state at all.
| Industry | NAICS | Leading State | Share of US Employment |
|---|---|---|---|
| Silver ore mining | 212222 | Idaho | See Report |
| Phosphate rock mining | 212392 | Florida | See Report |
| Iron ore mining | 21221 | Minnesota | See Report |
| Anthracite mining | 212113 | Pennsylvania | See Report |
| Motor home manufacturing | 336213 | Indiana | See Report |
| Carpet and rug mills | 31411 | Georgia | See Report |
| Hosiery and sock mills | 31511 | North Carolina | See Report |
The mining entries are unsurprising once stated — ore is where the ore is. The manufacturing entries are the interesting ones, because nothing physical compels them. Motor homes, carpet and hosiery concentrated for historical reasons and then stayed concentrated, because a supplier base, a trained workforce and a set of established relationships are as immobile in practice as a mineral deposit.
Need the numbers for silver ore mining?
The federal record for NAICS 212222: headline figures, the seven-year Census series, every reportable state and official concentration, with a source and provenance sheet. No written analysis.
The Three States That Lead Almost Everything #
At the other end of the telescope, the question is not where any one industry sits but how many industries each state leads. Here the concentration is even starker than the single-state cases, and it is not the famous clusters doing the work.
California, Texas and New York are the largest employer in more than two thirds of all NAICS-classified industries between them, with California alone leading a plurality. The scale of that is easy to under-read: it means that for most American industries, the state with the most workers in it is one of three, and the remaining forty-odd states share what is left.
The practical consequence is that most competitive analysis conducted at the national level is implicitly analysing a handful of state markets, without saying so.
Why Industries Concentrate Where They Do #
Four forces do nearly all of the work, and they explain the map better than any account of state policy.
Resource endowment fixes extraction industries absolutely — an ore body cannot relocate. Transport economics fixes anything heavy or bulky near ports, rivers and rail. Agglomeration fixes industries that need a deep specialist labor pool and a dense supplier base, which is why film production, aerospace components and specialist manufacturing cluster long after the original reason has faded. And historical accident fixes more than economists like to admit: an industry that started somewhere often stays there because moving is expensive and the reasons to move are rarely decisive.
What Geographic Concentration Means for Market Research #
Three practical rules follow, and each of them changes how an industry should be researched.
First, check concentration before trusting any national figure. If one state holds most of an industry, the national average is that state's number with extra steps. Second, a concentrated industry has a concentrated competitive set, which means the barriers to entry are usually higher than a national market-size figure suggests. Third, geography and market concentration are different things and should not be confused: an industry can be spread across forty states and still be dominated by four firms, or sit in one state and be highly fragmented within it.
Every VantaInsights industry report carries the full state-level distribution — employment, establishments and average pay for each state — alongside official concentration data and the multi-year national series.