State Populations

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State Populations

Pennsylvania, Illinois, and Texas are three of the most populated states in the United States with estimated populations of over 12.8 million, 12.6 million, and 29.4 million respectively. In order to provide a consistent overview, population data for each state, including county data and city data, was take from 2020 estimates provided by World Population Review. All population data is estimated based off of growth rates from the last Census. Below is an overview of findings.


  • The current estimated population of Pennsylvania is 12,820,878. The state has an estimated population growth rate of .24%.
  • Pennsylvania has 67 counties but only 56 cities.
  • The most populous county is Philadelphia County with a population of 1.58 million. This is followed by Allegheny County with 1.23 million residents, Montgomery County (820,700), Bucks County (626,800), and Delaware County (564,000). Over 37% of Pennsylvania residents reside in these five counties.
  • Pittsburgh is the most populous city in Pennsylvania with a population of 1.56 million. The next four most populous cities are Pittsburgh (304.400), Allentown (120,200), Erie (99,500) and Reading (87,900). Over 17% of the population of Pennsylvania reside in these five states.


  • The 2020 estimated population for Illinois is 12,659,682. Illinois is only one of 7 states that has a negative estimated growth rate at -.17%.
  • Illinois has 102 counties and 1,298 cities.
  • The most populous county is Cook County with 5,238,216 people. Neighboring Cook County is the next largest county, Dupage, with 933,736 people. Almost 50% of Illinois residents live in just these two counties.
  • The next three most populous counties are Lake County (700,800), Will County (692,300), and Kane County (534,200).
  • The most populous city is Chicago with 2.7 million residents. The next most populous city is Aurora with just over 200,000 residents. This is followed by Joliet (149,600), Naperville (147,900), and Rockford (145,300).
  • The majority of the population of Illinois lives in the North East portion of the state in the metropolitan area of Chicago, known as Chicagoland. This area is made up of several counties and many smaller cities, as well as Chicago, and has an estimated population of 8.3 million, over 65% of the population.


  • Texas has an estimated 2020 population of 29,472,295. It is the third fastest growing state in the U.S. with an estimated growth rate of 1.8%.
  • Texas has 254 counties and 1,218 cities.
  • The two most populated counties Harris and Dallas Counties. Harris County has an estimated population of 4,699,000 and Dallas County has a population of 2,638,000. These are followed by Tarrant County (2,085,000), Bexar County (1,986,000), and Travis County (1,249,000).
  • The most populous city in Texas is Houston with an estimated population of 2.4 million. This is followed by San Antonio (1.6 million), Dallas (1.4 million), Austin (1 million), and Fort Worth (914,000).
  • The Dallas/Ft. Worth (DFW) Metro Area is made up of 13 counties and has a total estimated population of 7.4 million, or 25% of the state population. The Greater Houston Area is made up of 9 counties and has an estimated population of 7 million, or 24% of the state population.