Zip Code 45820 — Cairo, OH
45820 is a ZIP Code associated with Cairo, OH, located within Allen. 45820 ranks #10 out of 13 ZIP codes in Allen County by population (and #1002 out of 1,232 in OH). The area supports an estimated population of 581 residents across Data Pending housing units, with a population density of 809.8 people per square mile.
WorldPlaceData database updated: October 2026
📍 View location on OpenStreetMap (40.830740, -84.084730)
| Data Metric | Local Statistic |
| Postal / Zip Code | 45820 |
| Primary City | Cairo |
| State / Province | OH |
| County | Allen |
| Total Population | 581 |
| Median Household Income | Data Pending |
| Total Housing Units | Data Pending |
| Population Density | 809.8 people/sq mi |
| Timezone | America/New_York |
How 45820 Compares
| Metric | ZIP 45820 | Allen County | OH State Average |
| Population | 581 | 108,577 (Total) | 11,810,293 (Total) |
| Average ZIP Income | Data Pending | N/A | N/A |
| Population Density | 809.8 /sq mi | -- | -- |
| County Pop Rank | #10 of 13 | -- | -- |
Nearby ZIP Codes
Data Sources & Methodology: Geographic coordinates and ZIP Code assignments are derived from underlying geographic and postal datasets. Note that ZIP Codes are USPS postal delivery areas, while Census ZCTAs are statistical approximation areas. Read full methodology →