US Housing Age Ranking: Oldest vs. Newest Counties

When evaluating residential real estate across major American counties, the age of a region's housing stock offers crucial context regarding potential infrastructure considerations. Building materials and standards vary considerably across eras. For instance, knob-and-tube wiring was standard before roughly 1950, galvanized steel supply piping was common before roughly 1970, and federal lead-based paint disclosure applies to homes built before 1978.

Across the 31 counties covered in this data set, the proportion of vintage housing varies drastically. In long-established urban centers, a majority of residential buildings were erected in the first half of the twentieth century. Conversely, Sunbelt metro areas saw their primary expansion decades later, resulting in residential landscapes dominated by late-twentieth-century construction.

Understanding these regional variations helps contextualize what buyers and researchers might expect when reviewing aggregate housing profiles. The table below outlines the share of housing built before 1950 and before 1980 across the tracked jurisdictions.

The Full Ranking

What This Data Shows

The dataset reveals a striking geographic divide between historic Northeastern urban cores and modern Sunbelt metro areas. In long-established eastern counties, pre-1950 construction forms the backbone of the residential landscape. Kings County, NY leads all covered counties, with 55.6% of housing built before 1950 and 81.0% built before 1980. Philadelphia County, PA follows closely, recording 50.6% before 1950 and 84.2% before 1980. In fact, four of the top five counties with the highest pre-1950 share are New York City boroughs, including New York County, NY (49.2% before 1950, 78.7% before 1980), Bronx County, NY (44.4% before 1950, 79.7% before 1980), and Queens County, NY (44.3% before 1950, 83.6% before 1980).

Conversely, the bottom five counties reflect major post-war expansion in the West and Southeast. Clark County, NV exhibits the newest housing profile, with a minimal 1.0% built before 1950 and 17.8% before 1980. Florida and Arizona counties mirror this trend: Broward County, FL shows 1.9% before 1950, Maricopa County, AZ reports 2.1% before 1950 and 29.4% before 1980, Palm Beach County, FL stands at 2.8% before 1950 and 33.7% before 1980, and Orange County, FL accounts for 3.0% before 1950 and 27.1% before 1980.

Interestingly, the pre-1980 metrics highlight secondary growth phases. While Broward County, FL has very little pre-1950 housing (1.9%), over half its stock (50.3%) was built before 1980, reflecting significant mid-century development. While these aggregate statistics do not indicate whether individual structures have undergone system updates, they highlight where older material standards—such as pre-1970 galvanized piping or pre-1950 wiring practices—were historically most widespread.

Methodology

This report utilizes U.S. Census Bureau American Community Survey (ACS) 5-year housing-age estimates across the 31 covered counties. Data categorizes housing stock into established age brackets, specifically capturing structures built before 1950 and before 1980. The 1950 benchmark aligns with the era when knob-and-tube wiring was standard. Because Census reports housing age in decade buckets, 1980 serves as the nearest clean decade boundary above 1978, the federal cutoff year for lead-based paint disclosures. Consequently, the pre-1980 metric provides a practical proxy for housing built during eras when lead paint and galvanized steel piping were prevalent.