Just for comparison sakes
Ten most populous counties
Los Angeles County, California 9,818,605
Cook County, Illinois 5,194,675
Harris County, Texas 4,092,459
Maricopa County, Arizona 3,817,117
San Diego County, California 3,095,313
Orange County, California 3,010,232
Kings County, New York 2,504,700
Miami-Dade County, Florida 2,496,435
Dallas County, Texas 2,368,139
Queens County, New York 2,230,722
Ten most built counties (total # of units) - red lower in rank than above, blue higher
Los Angeles County, California 3,445,076
Cook County, Illinois 2,180,359
Maricopa County, Arizona 1,639,279
Harris County, Texas 1,598,698
San Diego County, California 1,164,786
Orange County, California 1,048,907
Kings County, New York 1,000,293
Miami-Dade County, Florida 989,435
Dallas County, Texas 943,257
King County, Washington 851,261
The 11 counties with more than 100k vacant units
Maricopa County, Arizona 227,696
Cook County, Illinois 214,003
Los Angeles County, California 203,872
Harris County, Texas 163,543
Clark County, Nevada 124,978
Broward County, Florida 124,341
Miami-Dade County, Florida 122,083
Palm Beach County, Florida 120,367
Wayne County, Michigan 118,944
Riverside County, California 114,447
Lee County, Florida 111,281
Ten highest vacancy rates (out of the 100 most built counties)
Lee County, Florida 29.99%
Ocean County, New Jersey 20.48%
Polk County, Florida 19.11%
Palm Beach County, Florida 18.11%
Pinellas County, Florida 17.42%
Baltimore city, Maryland 15.77%
Broward County, Florida 15.34%
Brevard County, Florida 14.89%
Clark County, Nevada 14.87%
Wayne County, Michigan 14.48%
Ten lowest vacancy rates (out of the 100 most built counties)
Fairfax County, Virginia 4.01%
Nassau County, New York 4.23%
Santa Clara County, California 4.39%
Norfolk County, Massachusetts 4.60%
Middlesex County, New Jersey 4.62%
Bergen County, New Jersey 4.73%
San Mateo County, California 4.87%
Montgomery County, Maryland 5.01%
El Paso County, Texas 5.09%
Middlesex County, Massachusetts 5.12%