Populations continue to decline in Westmoreland, Allegheny counties

As populations across Pennsylvania increased over the past 10 years, Westmoreland and Allegheny counties have seen the opposite effect.

New data from the American Community Survey shows that from 2010-19, Westmoreland County lost more than 16,000 people with the population of Allegheny County dropping by about 7,500. Those numbers aren’t necessarily surprising, though, given the decrease across both counties each year. The population in Allegheny is now estimated to be 1,221,744, with Westmoreland at 352,590.

Across the state, the population increased by about 92,000 people, according to the ACS, which is conducted every year, surveying about 3.5 million people across the country. A March census report shows several counties — including Cumberland, Lebanon, Lehigh and Chester — have seen population increases in the past decade.

The increase across Pennsylvania is on track with estimates for the country, where the population also grew over the past decade, according to a demographic analysis released this week by the U.S. Census Bureau. The analysis is completed every decade before census results are released to help show the accuracy of the once-a-decade survey.

Based on birth and death rates as well as national migration and Medicare records, figures show that in 2020 the country grew to more than 332.6 million people by April 1. That is about 24.2 million people more than the 2010 demographic analysis.

Census officials gave a national population range of 330.7 million to 335.5 million to account for levels of uncertainty in data.

“We have seen an increase in the size of the population, which is what we would expect over 10 years,” said Eric Jensen, a senior technical expert for demographic analysis with the Census Bureau, noting that the median age in the United States is about 38.

Of the total number of people across the country, about 13.7% of the population is estimated to be Black alone while 15.1% is estimated to be Black alone or in a combination of other races. For the population under the age of 30, an estimated 24.6% are Hispanic.

Data collected in the analysis will be compared with the 2020 census results when they are released to produce possible error estimates by age, sex, broad race and Hispanic origin groups. A report detailing estimates by the analysis, as well as over and under counts, will be released next year.

While it is not clear when the 2020 census data will be released, the collection this year was marred by the coronavirus pandemic, court cases brought by the Trump administration and an uncertain collection deadline that came to an abrupt end in October.

A timeline on the census website shows officials hope to deliver population counts as close to Dec. 31 as possible.

“Today’s demographic analysis release marks a major milestone in the 2020 census timeline, but we have a lot more work ahead of us,” Jensen said Tuesday.