U.S. Census Bureau

subcounty population datasets

All files are comma separated values (.csv) format.

File layout (2k) Help with .csv files

Alabama (97k) Alaska (30k) Arizona (21k)
Arkansas (102k) California (109k) Colorado (62k)
Connecticut (29k) Delaware (11k) District of Columbia (1k)
Florida (91k) Georgia (130k) Hawaii (1k)
Idaho (42k) Illinois (664k) Indiana (340k)
Iowa (175k) Kansas (348k) Kentucky (107k)
Louisiana (69k) Maine (53k) Maryland (34k)
Massachusetts (53k) Michigan (344k) Minnesota (481k)
Mississippi (73k) Missouri (250k) Montana (33k)
Nebraska (185k) Nevada (7k) New Hampshire (31k)
New Jersey (157k) New Mexico (26k) New York (327k)
North Carolina (131k) North Dakota (241k) Ohio (498k)
Oklahoma (119k) Oregon (51k) Pennsylvania (555k)
Rhode Island (8k) South Carolina (63k) South Dakota (198k)
Tennessee (87k) Texas (269k) Utah (47k)
Vermont (40k) Virginia (64k) Washington (61k)
West Virginia (56k) Wisconsin (349k) Wyoming (22k)