Men per 100 women in every US county, by age
All 17 five-year age bands, birth to 80+, across 3,135 areas. American Community Survey 2020–2024.
Purple counties have more women, orange more men. The scale is clamped at 85 and 115, so the oldest bands sit hard against the purple end.
Birth is flat. Old age is not.
- The 0–4 map is flat. 104.6 boys per 100 girls nationally, and effectively the same figure in every county. That is just the natural human sex ratio at birth — about 105 worldwide, 103 to 107 in most countries, and stable across populations and eras. Values persistently above that range are the signature of sex selection. The US sits inside it.
- It crosses 100 in the late forties and never comes back. 99.6 at 45–49, 90.4 at 65–69, 66.3 at 80+.
Every band
| Age | National | Most men | Ratio | Most women | Ratio |
|---|---|---|---|---|---|
| 0-4 | 104.6 | Fayette, Pennsylvania | 111 | Curry, New Mexico | 96 |
| 5-9 | 105.0 | Herkimer, New York | 116 | District of Columbia | 99 |
| 10-14 | 104.9 | Maverick, Texas | 128 | Williams, North Dakota | 100 |
| 15-19 | 104.7 | Onslow, North Carolina | 165 | Madison, Idaho | 50 |
| 20-24 | 104.3 | Onslow, North Carolina | 220 | New York County (Manhattan) | 83 |
| 25-29 | 103.0 | Walker, Texas | 177 | District of Columbia | 80 |
| 30-34 | 102.1 | Allegany, Maryland | 149 | Colbert, Alabama | 80 |
| 35-39 | 101.7 | Nash, North Carolina | 132 | Richland, South Carolina | 88 |
| 40-44 | 101.2 | Allegany, Maryland | 126 | Henry, Georgia | 89 |
| 45-49 | 99.6 | Fremont, Colorado | 137 | Rockdale, Georgia | 75 |
| 50-54 | 99.4 | Anderson, Texas | 163 | Cumberland, North Carolina | 83 |
| 55-59 | 97.1 | Walker, Texas | 131 | Bronx, New York | 86 |
| 60-64 | 94.8 | Santa Clara, California | 102 | Philadelphia, Pennsylvania | 88 |
| 65-69 | 90.4 | San Francisco, California | 95 | Shelby, Tennessee | 84 |
| 70-74 | 87.4 | Otter Tail, Minnesota | 100 | Philadelphia, Pennsylvania | 77 |
| 75-79 | 82.5 | Hawaii County (Big Island) | 106 | Bronx, New York | 65 |
| 80+ | 66.3 | Yuma, Arizona | 88 | Shelby, Tennessee | 51 |
Extremes are limited to areas with at least 3,000 people in that band, so a 40-person county cannot take the top slot. Figures are shrunk toward the national value in proportion to each county's published margin of error. The CSV carries the raw counts alongside.
Where the map is wrong
- Connecticut is drawn at state level. ACS reports it on nine planning regions, which replaced its counties for statistical use in 2022 and do not nest into the county shapes the standard boundary file still ships.
- The colour scale saturates at the top end of the age range. By 80+ the national figure is 66.3, below the purple end of the scale, so almost every county pegs. The line chart under the map is the only thing showing how far it actually falls.
Sources
Age by sex: US Census Bureau, American Community Survey 2020–2024 5-year estimates, table B01001, county level, with the published 90% margins of error. Boundaries: US Census TIGER, via the topojson/us-atlas distribution. Built with Python and matplotlib. For the natural sex-ratio-at-birth benchmark, see Our World in Data.
The same census data drives sex ratio by region across every market on the site. The US deep-dive, which adds cost, safety, visa and climate on top of it, is behind the Pro gate.