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Definitions

Gross domestic product (GDP) by county is the market value of goods and services produced by the labor and property located in a county. GDP by county is the substate counterpart of the nation's GDP, the Bureau's featured and most comprehensive measure of U.S. economic activity.

Current-dollar statistics are valued in the prices of the period when the transactions occurred—that is, at “market value.” They are also referred to as “nominal GDP” or “current-price GDP.”

Real values are inflation-adjusted statistics—that is, these exclude the effects of price changes.

Contributions to growth are an industry’s contribution to the county’s overall percent change in real GDP. The contributions are additive and can be summed to the county’s overall percent change.

Personal income is the income received by, or on behalf of, all persons from all sources: from participation as laborers in production, from owning a home or business, from the ownership of financial assets, and from government and business in the form of transfers. It includes income from domestic sources as well as the rest of the world. It does not include realized or unrealized capital gains or losses.

Personal income is measured before the deduction of personal income taxes and other personal taxes and is reported in current dollars (no adjustment is made for price changes).

County personal income differs slightly from the estimate of U.S. personal income in the National Income and Product Accounts because of differences in coverage, in the methodologies used to prepare the estimates, and in the timing of the availability of source data. In BEA’s county statistics, estimates of personal income for the United States is the sum of the county estimates and the estimate for the District of Columbia.

Per capita personal income is calculated as the total personal income of the residents of a county divided by the population of the county. In computing per capita personal income, BEA uses U.S. Census Bureau midyear population estimates.

Statistical conventions

Quantities, or “real” measures, are expressed as index numbers with a specified reference year equal to 100 (currently 2017). Quantity indexes are calculated using a Fisher chain-weighted formula that incorporates weights from two adjacent periods (quarters for quarterly data and annuals for annual data). “Real” dollar series are calculated by multiplying the quantity index by the current dollar value in the reference year and then dividing by 100. Percent changes calculated from chained-dollar levels and quantity indexes are conceptually the same; any differences are due to rounding.

Chained-dollar values are not additive, because the relative weights for a given period differ from those of the reference year.

Chained-dollar values of GDP by county are derived by applying national chain-type price indexes to the current dollar values of GDP by county for 65 North American Industry Classification System-based industry sectors. The chain-type index formula that is used in the national accounts is then used to calculate the values of total real GDP by county and real GDP by county at more aggregated industry levels. Real GDP by county may reflect a substantial volume of output that is sold to other areas and counties. To the extent that a county's output is produced and sold in national markets at relatively uniform prices (or sold locally at national prices), real GDP by county captures the differences across counties that reflect the relative differences in the mix of goods and services that the counties produce. However, real GDP by county does not capture geographic differences in the prices of goods and services that are produced and sold locally.

GDP by county statistics released today are consistent with the GDP by state statistics released on September 26, 2025, which were based on the September 2025 annual update of the National Income and Product Accounts.

Uses of GDP and personal income by county statistics

GDP and personal income by county statistics provide a framework for analyzing current economic conditions in each county and can serve as a basis for decision-making. For example:

  • Federal government agencies use the statistics in forecasting models to project energy and water use. The statistics are also used as a basis for allocating funds and determining matching grants to states.
  • State governments use the statistics to project tax revenues and the need for public services.
  • Academic regional economists use the statistics for applied research.
  • Businesses, trade associations, and labor organizations use the statistics for market research.