Harris County, Texas is 51 times larger than Manchester, New Hampshire.
Area: 4,589 km2 calculated
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
Area: 90 km2 calculated
Manchester is the largest city in the U.S. state of New Hampshire, the tenth largest city in New England, and the largest city in northern New England, an area comprising the states of Maine, New Hampshire, and Vermont. It was first named by the merchant and inventor Samuel Blodget. Wikipedia