Harris County, Texas is 86% larger than Cook County, Illinois.
Area: 2,468 km2 calculated
Population: 5,231,351 (2012)
Cook County is a county in the United States state of Illinois. As of the 2010 census, the population was 5,194,675. Wikipedia
Area: 4,589 km2 calculated
Population: 4,253,700 (2012)
Harris County is a county in the U.S. state of Texas. As of the 2010 census, the population was 4,092,459, making it the most populous county in Texas and the third-most populous in the United States. Wikipedia