Fastest Growing Counties in America

US counties ranked by total population. The most populous counties are concentrated around major metro areas. Population figures from the Census Bureau's Population Estimates Program.

Ranked by Population. Click any location to see its full Census data profile. All figures are from the U.S. Census Bureau ACS 5-Year Estimates, 2023, so they are directly comparable across locations.

#	Location	Population
1	Los Angeles County, California	9,848,406
2	Cook County, Illinois	5,185,812
3	Harris County, Texas	4,758,579
4	Maricopa County, Arizona	4,491,987
5	San Diego County, California	3,282,782
6	Orange County, California	3,164,063
7	Miami-Dade County, Florida	2,685,296
8	Kings County, New York	2,646,306
9	Dallas County, Texas	2,603,816
10	Riverside County, California	2,449,909
11	Queens County, New York	2,330,124
12	Clark County, Nevada	2,293,764
13	King County, Washington	2,262,713
14	San Bernardino County, California	2,187,816
15	Tarrant County, Texas	2,135,743
16	Bexar County, Texas	2,037,344
17	Broward County, Florida	1,946,127
18	Santa Clara County, California	1,903,297
19	Wayne County, Michigan	1,773,767
20	Alameda County, California	1,651,949
21	New York County, New York	1,627,788
22	Middlesex County, Massachusetts	1,622,896
23	Sacramento County, California	1,584,047
24	Philadelphia County, Pennsylvania	1,582,432
25	Suffolk County, New York	1,525,680
26	Palm Beach County, Florida	1,507,453
27	Hillsborough County, Florida	1,489,634
28	Orange County, Florida	1,440,471
29	Bronx County, New York	1,419,250
30	Nassau County, New York	1,388,138
31	Franklin County, Ohio	1,321,635
32	Travis County, Texas	1,307,625
33	Oakland County, Michigan	1,272,294
34	Hennepin County, Minnesota	1,268,903
35	Cuyahoga County, Ohio	1,249,418
36	Allegheny County, Pennsylvania	1,240,476
37	Salt Lake County, Utah	1,184,689
38	Contra Costa County, California	1,161,458
39	Wake County, North Carolina	1,151,009
40	Fairfax County, Virginia	1,144,474
41	Mecklenburg County, North Carolina	1,130,906
42	Collin County, Texas	1,116,601
43	Fulton County, Georgia	1,068,507
44	Montgomery County, Maryland	1,057,586
45	Pima County, Arizona	1,049,947
46	Fresno County, California	1,012,152
47	Duval County, Florida	1,007,189
48	Honolulu County, Hawaii	1,003,666
49	Westchester County, New York	996,888
50	St. Louis County, Missouri	996,618