Geography quiz
US cities over 100,000 starting with O
Every US city starting with O that had 100,000 or more residents at the 2020 Census (1 April 2020): 11 in all, largest first. The population appears as each row fills.
- Format
- Type them all
- Items
- 11 answers
- Limit
- 2:00
- Level
- Medium
- Checked
- 2026.10.03
- Answers
- 11
- Time limit
- 2:00
- Order
- Any order
- Matching
- Case and accents ignored
- Type an answer; it files itself the moment it matches.
- One answer can fill several slots.
- Give up at any time to see what you missed.
- Pause whenever you like (Esc). The board hides while the clock is stopped.
Name every US city over 100,000 that starts with O.
| No. | State | City | 2020 Census |
|---|---|---|---|
| 1 | Oklahoma | Not found yet | |
| 2 | Nebraska | Not found yet | |
| 3 | California | Not found yet | |
| 4 | Florida | Not found yet | |
| 5 | California | Not found yet | |
| 6 | Kansas | Not found yet | |
| 7 | California | Not found yet | |
| 8 | California | Not found yet | |
| 9 | Kansas | Not found yet | |
| 10 | California | Not found yet | |
| 11 | Texas | Not found yet |
About this quiz
Population here means the 2020 Census count, taken on 1 April 2020. A city is an incorporated place: places that are not incorporated, such as Arlington in Virginia or Paradise in Nevada, are left out, and merged city and county governments such as Nashville, Louisville and Indianapolis count the city part.
- Oklahoma City, Oklahoma, is the largest on this list, with 681,054 residents.
- California has the most cities starting with O: 5 of the 11.
- The smallest is Odessa, Texas, with 114,428.
- Across the country, 322 cities had 100,000 or more residents at the 2020 Census.
Sources
- [1]US Census Bureau. 2020 Census Redistricting Data (Public Law 94-171) Summary Files.
- [2]US Census Bureau. City and Town Population Totals: incorporated places file.
Note on the data. Populations are 2020 Census counts (1 April 2020), read on 3 October 2026 from the place records (summary level 160, POP100) in the geographic header file of every state's P.L. 94-171 redistricting file on www2.census.gov. The 2020 count was chosen over the yearly estimates because it does not change. The set of cities is the Census Bureau's incorporated place list (summary level 162 of its City and Town Population Totals file), so census designated places such as Arlington, Virginia and Paradise, Nevada and townships are left out, and Honolulu is the Urban Honolulu place the Bureau carries for Hawaii. Consolidated governments use the Bureau's balance record (Nashville, Indianapolis, Augusta, Athens); Louisville adds the two place records the 2020 file splits it into, 386,884 for the balance and 246,161 for Louisville city, 633,045 in all. Tuscaloosa (99,600) and Kenosha (99,986) were counted just under 100,000 and are left out even though later revised bases put them over. Labels are common names: Boise for Boise City, Ventura for San Buenaventura (Ventura).
Last checked October 3, 2026
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