Section
Counties
"What county is this city in" lookups -- including the cities that straddle more than one county, which a one-line answer usually misses.
Index
01 What County Is Chicago In? All 84 of Chicago's ZIP codes sit inside Cook County; only the city's O'Hare strip dips into DuPage. Cook is the second-most-populous US county, and it's growing again, not losing ground to Harris County. 02 What County Is Houston In? Houston's 178 ZIP codes sit entirely inside Harris County; only small annexed strips of the city itself dip into Fort Bend and Montgomery. Harris is closing the population gap on Chicago's Cook County. 03 What County Is San Antonio In? 82 of San Antonio's 83 ZIP codes sit in Bexar County, Texas; the other reaches into Comal County next door. Bexar itself once covered nearly all of West Texas, before 128 of today's counties were carved out of it. 04 Baltimore City vs County: What's the Difference? Baltimore City is not in Baltimore County. It has been an independent city since 1851, yet its ZIP codes all sit in the 212 range the county also uses. 05 Why Is Brooklyn Called Kings County? Brooklyn is Kings County, a name the English gave it in 1683 for Charles II. Each NYC borough matched to its county, ZIP range and area codes.