Home Building Geography Index (HBGI)

The Home Building Geography Index (HBGI) is a quarterly measurement of building conditions across the country and uses county-level information about single-family and multifamily permits to gauge housing construction growth in various submarkets. The HBGI for the second quarter of 2026 focuses on the population density-based delineation of home building that has been the mainstay of the HBGI.

Key Findings for Q2 2026:

• Single-family construction remained weak with construction declining year-over-year in six of seven geographies, although contractions generally eased from Q1. Large metro core counties posted the steepest decline at 13.9%, while small metro outlying counties were the only geography to grow, rising 0.9%.
• Single-family construction continued shifting toward smaller markets as large metro core counties lost 1.3 percentage points of market share, falling to 14.6%. Meanwhile, small metro outlying counties recorded the largest gain, reflecting the continued movement of home building toward smaller, less densely populated markets.
• Multifamily construction strengthened across most markets with six of seven geographies expanding, led by a rebound in large metro core counties. Core and suburban large-metro counties gained market share and together accounted for 62.7% of multifamily construction.

Download the data file of the full HBGI findings

Regional Building Growth Conditions

NAHB classified all counties in the U.S. into one of seven regional categories based on population density and regional location. For each area, NAHB tracked single-family and multifamily growth rates (not seasonally adjusted) and market shares. An interactive map of the latest data is shown below, followed by definitions of each category.

Definitions of Regional Categories

• Large Metro Core Counties
  • Densely populated central counties within major metropolitan areas (over 1 million population). These are the urban cores with the highest population density.
• Large Metro Suburban Counties
  • Suburban counties surrounding the core of major metros (over 1 million). They are less dense than core counties but still part of large urban regions.
• Large Metro Outlying Counties
  • Counties on the outer edge of major metro areas, typically lower density and farther from the urban core but still tied economically to large metros.
• Small Metro Core Counties
  • The central counties of smaller metropolitan areas (under 1 million population). They are the most populated/dense part of smaller metro regions.
• Small Metro Outlying Counties
  • Lower-density counties located on the periphery of small metropolitan areas.
• Micro Counties
  • Low‑density, low‑population counties that form micropolitan areas, typically centered around small towns with 10,000–50,000 residents. These counties saw notable construction growth.
• Non metro/micro counties
  • The most rural areas with no metro or micropolitan designation, very low density and population.

Update to County Populations

Beginning with the second quarter of 2022, NAHB updated the HBGI to use the most recent county population estimates from the 2020 5-year American Community Survey (ACS). This necessitated a reclassification of county-level regional assignments, based on population density-based delineations. The number of counties in the HBGI is 3,133, with the newest updates for counties in Virginia and Hawaii.