Genealogy Today | Directory Allegheny County U.S. Census (1790 - 1930) Directory > Census Records > U.S.A. > Pennsylvania U.S. Federal Census records are divided into groups by state, then county, and in many cases by township as well.  1790 Census ADD NEW LISTING  USGenWeb5: 1790 Census Index - Allegheny 1790 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1790 Census  1800 Census ADD NEW LISTING  1800 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1800 Census  1810 Census ADD NEW LISTING  1810 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1810 Census  1820 Census ADD NEW LISTING  1820 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1820 Census  1830 Census ADD NEW LISTING  1830 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1830 Census  1840 Census ADD NEW LISTING  1840 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1840 Census  1850 Census ADD NEW LISTING  1850 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1850 Census  1860 Census ADD NEW LISTING  1860 Census - Pennsylvania - Allegheny County  from Ancestry.com Pennsylvania Allegheny and Butler Counties Federal Census Index, 1860 Ci  (limited availability) Information about the 1860 Census  1870 Census ADD NEW LISTING  1870 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1870 Census  1880 Census ADD NEW LISTING  1880 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1880 Census  1900 Census ADD NEW LISTING  Population4: 775,058 1900 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1900 Census  1910 Census ADD NEW LISTING  Population4: 1,018,463 1910 Census - Pennsylvania - Allegheny County  from Ancestry.com Pennsylvania, Allegheny County (1910 Miracode Census Index)  (limited availability) Information about the 1910 Census  1920 Census ADD NEW LISTING  Population4: 1,185,808 1920 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1920 Census  1930 Census ADD NEW LISTING  Population4: 1,374,410 1930 Census - Pennsylvania - Allegheny County  from Ancestry.com Information about the 1930 Census  Additional Information Allegheny

⁴ Population of Counties by Decennial Census: 1900 to 1990, U.S. Bureau of the Census, 1995

⁵ The USGenWeb Census Project, USGenWeb Archives, 2004.