1920–1929 · 1,165,975 recorded births
Robert was the most common name given in Illinois across the 1920s, with 42,409 births in the decade. The state recorded 1,165,975 births in total over those years.
Names given far more often here than nationally in these years. The multiplier is conservative — it is the low end of the plausible range, so a name carried by a handful of births does not outrank one carried by hundreds.
| Name | Births | vs national |
|---|---|---|
| Lavergne | 197 | 12× |
| Rochelle | 138 | 5× |
| Casimir | 381 | 5× |
| Sherwin | 92 | 4× |
| Christ | 143 | 4× |
| Bruno | 511 | 4× |
| Colette | 106 | 4× |
| Shirlee | 309 | 4× |
| Rank | Name | Births |
|---|---|---|
| #1 | Robert | 42,409 |
| #2 | Mary | 35,034 |
| #3 | John | 33,197 |
| #4 | William | 28,828 |
| #5 | Dorothy | 23,852 |
| #6 | James | 22,908 |
| #7 | Betty | 19,668 |
| #8 | Helen | 17,475 |
| #9 | Charles | 16,958 |
| #10 | Richard | 16,750 |
| #11 | Edward | 15,423 |
| #12 | George | 15,399 |
| #13 | Donald | 14,877 |
| #14 | Joseph | 13,294 |
| #15 | Margaret | 12,254 |
| #16 | Ruth | 11,707 |
| #17 | Virginia | 11,092 |
| #18 | Shirley | 10,001 |
| #19 | Frank | 9,882 |
| #20 | Raymond | 9,199 |
| #21 | Harold | 8,958 |
| #22 | Thomas | 8,239 |
| #23 | Evelyn | 7,695 |
| #24 | Walter | 7,634 |
| #25 | Lorraine | 7,632 |
Source: U.S.A. Social Security Administration. State records begin in 1910. Names given to fewer than five babies in a state in a year are withheld at source. namelegacy.org