County Population Ranking, With Ten Year Trends Source: US Census Census Population Change from 1990 to 2000 County Name State 1990 2000 Number Percent Los Angeles County CA 8,863,164 9,519,338 656,174 7.4 Cook County IL 5,105,067 5,376,741 271,674 5.3 Harris County TX 2,818,199 3,400,578 582,379 20.7 Maricopa County AZ 2,122,101 3,072,149 950,048 44.8 Orange County CA 2,410,556 2,846,289 435,733 18.1 San Diego County CA 2,498,016 2,813,833 315,817 12.6 Kings County NY 2,300,664 2,465,326 164,662 7.2 Miami-Dade County FL
