Philadelphia gained roughly 77,800 residents between 2010 and 2020, growing the city’s population to more than 1.6 million, according to the first local and demographic results from the 2020 census, released Thursday.

The city’s population last topped 1.6 million in the 1980 census. Philadelphia’s 5.1% increase in population in the 2010s was the largest 10-year population gain since 1950, when the city grew by 7.3%. Philadelphia keeps its rank as the country’s sixth-largest city after Phoenix overtook it within the last few years.

Gains in the Hispanic and non-Hispanic Asian populations drove Philadelphia’s growth. The Census Bureau’s classification of “Hispanic or Latino” includes people of any race who describe themselves as such.

The entire Philadelphia region is growing in population and even more so in diversity. The number of people living in the city and its surrounding counties grew by 5%, but the Hispanic population grew by 36%, the Asian population grew by 39%, and the white population declined by 4%.

The white population fell in all eight counties. The Hispanic and Asian populations grew across those counties. The Black population fell in two of them — Chester County and Philadelphia.

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The decline in Philadelphia’s Black population — a loss of about 30,500 people — is the city’s steepest in history. The drop in the city’s white population — about 11,800 people — is the smallest since the 1940s, when Philadelphia added roughly 14,000 white residents.

The city’s population of Hispanic residents grew by about 50,700 and Asian residents by 36,900.

The bureau said these numbers reflect both actual changes in demographics and improvements in question designs, data processing, and coding that allowed for a more accurate picture of how people identify. Nationwide, the percentage of people who reported multiple races changed more than the percentage of each one-race group, according to the Census Bureau. The multiracial population grew from 2.9% of the country in 2010 to 10.2% in 2020.

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The 2020 U.S. population counts show continued migration to the South and Southwest and population losses in the Mississippi Delta and Appalachia. The Northeast is the slowest-growing region in the country.

Between 2010 and 2020, counties with the largest populations grew the most. Those with 100,000 or more people grew by 9.1%.

The numbers also indicate that the white population is aging and has fallen to its smallest share of the total population on record, though there are some exceptions. The share of the white population actually grew in coastal communities in the Carolinas and Virginia, as well as in counties stretching through the midsections of Georgia and Alabama. The population under age 18 is increasingly diverse.

Estimates from previous years suggested that Philadelphia’s population peaked in 2018 before declining slightly in 2019, but the figure released by the Census Bureau on Thursday shows that trend was unlikely.

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Philadelphia grew by about 8,500 residents between the 2000 and 2010 census counts.

The city’s population peaked in 1950 at more than two million. It saw its biggest drop between 1970 and 1980, during which time it lost more than 260,000 residents. In the decades that followed, the population has hovered at more than 1.5 million.

City and state officials worry the census undercounted their residents due to adjustments in Census Bureau operations during the pandemic, a prolonged fight over a failed citizenship question that may have deterred immigrants from responding, and digital divides during the first decennial census in which everyone was encouraged to respond online.

Ron Jarmin, acting director of the Census Bureau, said Thursday that it is “too early to speculate” about undercounts or overcounts and that the population tallies “meet our high data quality standards.”

» READ MORE: Federal missteps in the 2020 Census could mean an undercount of Philly’s population

Population counts from the 2020 census will determine the distribution of hundreds of billions of federal dollars to state and local governments over the next decade for services such as housing and food assistance, medical centers, transportation, and education. Communities and neighborhood groups adjust plans for the future based on the makeup of residents and the addition or loss of people.

The once-a-decade, constitutionally mandated population count also will be used to redraw voting district boundaries and to redistribute U.S. House seats and Electoral College votes. In April, the Census Bureau released statewide population totals that confirmed Pennsylvania will lose one of its 18 House seats and one of its 20 Electoral College votes. New Jersey will keep its 12 House seats.

The drawing of political maps is high stakes for both parties: Republicans need to win just five seats to take back control of the House, and Pennsylvania and New Jersey have several competitive districts that, depending how they are redrawn, can benefit either side. And the state legislative maps will help determine state power. Now, with the official population data released, the scramble is on to draw those districts — and shape the balance of power in Harrisburg, Trenton, and Washington.

Staff writer Jonathan Lai and the Associated Press contributed to this article.