The 100 wealthy counties in America
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Executive summary
The map of America’s wealthiest counties is dominated by suburbs of tech and federal government hubs: recent reporting and compilations place Loudoun County, VA, and Bay‑Area counties such as San Mateo and Santa Clara among the top earners, with median household incomes often reported well above $150,000 and some county averages stretched past $200,000 in 2023 data [1] [2] [3]. A long-standing dataset compiled from the U.S. Census American Community Survey underpins many “top 100” lists and shows Virginia contributes the largest share of high‑income counties in that hundred (Virginia 18 counties), followed by California and Maryland [4].
1. Wealth concentrated in a few regions — tech and DC suburbs dominate
The wealthiest counties repeatedly cluster around the same economic engines: Silicon Valley and the broader Bay Area, Washington, D.C. suburbs in Northern Virginia and Maryland, and select resort or low‑population enclaves. Coverage in outlets from SmartAsset and regional demographic sites highlights San Mateo and Santa Clara counties as perennial Bay Area leaders and Loudoun and Fairfax among the richest in and around the capital region [2] [5] [1]. These are not random: high concentrations of high‑paying tech, biotech, finance and federal contractor jobs drive above‑average household incomes [1].
2. Different methods, different leaders — “median” vs “average” vs composite indexes
Public lists do not use a single standard. Some outlets report median household income (a common Census metric); others report average (mean) household income or a composite “wealth index” that mixes median income, investment income and home values [6] [2] [5]. That methodological difference changes rankings: places with a few extremely wealthy households can rank higher on mean income but not on median income, while composite measures can favor counties with high home values even if cash incomes are lower [6] [5].
3. What the “top 100” actually reflects — ACS sampling and time windows
The canonical compilation of the 100 highest‑income counties that many references draw on is based on the U.S. Census Bureau’s American Community Survey (ACS) multi‑year estimates and is reproduced in public resources like Wikipedia’s list, which uses ACS 5‑year data windows [4]. Those multi‑year windows smooth year‑to‑year volatility but also mean the lists reflect several years of incomes (e.g., 2017–2021 or 2016–2020), not a single calendar year snapshot [4].
4. State‑level concentrations: Virginia leads the count; California close behind
A headline pattern in the ACS‑based top‑100 listing: Virginia reportedly contains more counties in the top 100 than any other state (18 counties), followed by California and Maryland — a geographic footprint that underscores how regional job markets and suburbanization shape county incomes [4]. That distribution dovetails with separate state pages and reporting that show Loudoun County and others near DC ranking at the top of national lists [3] [1].
5. Small counties and high per‑capita anomalies: resort and low‑population effects
Some of the highest reported incomes come from small or low‑population counties (for example, Nantucket or Pitkin are frequently cited in state or national lists), where a small number of very high‑income households or seasonal residents can push county averages high [5] [7]. Analysts and data sites caution that averages and small sample sizes can exaggerate apparent prosperity compared with larger, more diverse counties [6] [7].
6. Reporting differences and competing lists — who to trust
No single outlet is definitive. Financial and local demographic sites (SmartAsset, county‑by‑state demographic pages) use differing data mixes (Census, IRS, Zillow, TRAC tax data), and magazine or newspaper lists may recast results for narrative impact [5] [8]. Wikipedia’s ACS‑based top‑100 table is explicit about its ACS source and time window and is the closest thing to a reproducible census‑based ranking cited across multiple summaries [4].
7. What’s missing or uncertain in current reporting
Available sources do not mention a single, definitive “100 wealthy counties” list published in 2025 using identical methodology across outlets; instead, different compilers publish overlapping but not identical rankings using median, mean, IRS or composite indexes [1] [6] [5] [4]. Detailed current median or mean values for every county in a consolidated top‑100 with a uniform year (e.g., 2025 median household income for all 100) are not present in these sources; users seeking that must consult ACS/US Census data directly or a single methodological compilation.
8. Bottom line for readers
If you want a reproducible, census‑rooted top‑100, rely on ACS‑based compilations (as summarized in the public list referenced by Wikipedia) and remember those rankings reflect multi‑year estimates and median or per‑capita choices that materially alter results [4]. If you prefer a picture that emphasizes asset wealth or home values, consult composite indexes (SmartAsset) or mean‑income lists from demographic publishers — but treat cross‑list comparisons cautiously because methodology changes who appears in the top slots [5] [6].