When Pittsburgh was built
The map has 117,325 buildings, every outline inside the city line in OpenStreetMap (and Microsoft’s, where OpenStreetMap has none), each joined to the parcel it stands on in Allegheny County’s property records. The county dates 99,780 of them, 85.0%. Colored by era, the city sorts itself: the nineteenth-century rowhouse neighborhoods by the rivers, the Central Northside, Lawrenceville and the South Side, where a fifth to a third of the buildings the county dates went up before 1900; Highland Park, Homewood, Regent Square and Beltzhoover, nearly all built from 1900 to 1939; and at the city’s edges Banksville, Stanton Heights and Westwood, built mostly after 1940.
75,594 of the buildings the county dates went up before 1940, three in four. The two decades from 1900 and the two from 1920 hold 34,474 and 33,764. Since 2000 the county has dated 1,882, most of them houses.
| Built | Buildings | Share | Year likely estimated |
|---|---|---|---|
| Before 1850 | 98 | 0.1% | 17.3% |
| 1850–1899 | 7,258 | 6.2% | 73.1% |
| 1900–1919 | 34,474 | 29.4% | 86.7% |
| 1920–1939 | 33,764 | 28.8% | 77.3% |
| 1940–1959 | 16,433 | 14.0% | 58.5% |
| 1960–1979 | 4,453 | 3.8% | 55.0% |
| 1980–1999 | 1,418 | 1.2% | 20.2% |
| 2000–2013 | 1,194 | 1.0% | 7.2% |
| 2014–today | 688 | 0.6% | 9.4% |
| No year | 17,545 | 15.0% | — |
The county’s roll describes residential buildings only. Offices, apartment blocks of five units or more, churches, schools and factories have no year in it, so 17,545 buildings, 15.0%, are grey on the map and stand all through the time-lapse: 14,152 of them on parcels that aren’t residential. Some are dated from EPA’s ENERGY STAR profiles, Wikidata and OpenStreetMap, and their card says which. Many of the county’s years are estimates: 68,501 buildings sit on round years the roll heaps up on, and 1900 alone holds 16,868, where the years either side hold a few hundred each. So read an era, not a year. A garage or carriage house takes its lot’s year, the main building’s, and is drawn paler too.
How tall
94,207 buildings, 80.3% of the city, have one or two floors, counting garages and sheds; 81 have thirteen or more, most of them Downtown, and two have fifty or more: the U.S. Steel Tower, with 64, and 500 Grant Street, with 55. Floors come from the county’s roll for a house and from OpenStreetMap for the rest.
ENERGY STAR
Under an ordinance passed in 2016, Pittsburgh’s non-residential buildings of 50,000 square feet or more report their energy and water use to the city every year, through EPA’s ENERGY STAR Portfolio Manager. The city doesn’t publish the results building by building yet: its benchmarking page lists the first dataset as coming soon. New York posts a grade at each building’s door; Pittsburgh doesn’t.
The public record building by building is EPA’s own: the buildings it has certified ENERGY STAR, each year a building scores 75 or more out of 100. 41 buildings in the city are on EPA’s registry. 11 were certified for 2025 or 2026, 6 last between 2020 and 2024, and 24 before 2020. A click shows a building’s latest score and how many years it has been certified.
Certification is voluntary and only for the best performers, so the map shows which buildings earned it, not how the rest of the city’s large buildings use energy.
Historic sites and districts
2,583 buildings stand in one of the city’s 21 historic districts, and 290 are on one of its 157 designated historic sites. Changing the outside of either, building new in a district or tearing down needs a certificate of appropriateness from the city’s Historic Review Commission. Where the county’s roll has it, a house’s card shows its style.
The floodplains and the slopes
924 buildings touch FEMA’s 100-year floodplain on the map that has set flood insurance in Allegheny County since 2014, 220 of them in the floodway, the channel a flood runs in. 893 more are in the 500-year floodplain. 226 houses in the 100-year floodplain have a basement, by the county’s records.
Pittsburgh’s other risk is its hillsides. 12,071 buildings, 10.3% of the city, stand in an area the city maps as prone to landslides.
These are FEMA’s and the city’s maps of chances, not predictions for any one building. A building is counted in a zone when its middle or any corner of its outline falls in it. New York’s study adds the floodplains the city projects for the 2050s and 2080s; Pittsburgh has no such maps.
What the data can’t say
The outlines are OpenStreetMap’s, a volunteer map kept closely in Pittsburgh: a building torn down may linger and a new one may be missing. Heights are OpenStreetMap’s where it has them, the county’s stories for a house, or Microsoft’s estimates from aerial imagery; 11,493 buildings have none of those and are drawn two floors tall. The county dates its houses, not its larger buildings. And the map is the city today: a building torn down is gone from it, so the time-lapse shows when today’s buildings went up, not the city as it stood in each year.
