Ille's name day is September 17 in Estonia.
Ille is a remarkably uncommon name in the United States, rarely appearing in records and not currently popular. It finds its strongest presence in Estonia, where it’s traditionally a masculine name, and to a lesser extent in other Baltic countries. The name likely developed as a short form of longer names containing the element 'Il-', suggesting noble or divine connections. Its limited usage indicates a strong cultural tie to its origins, and it evokes a sense of quiet strength and understated elegance. Ille is generally considered masculine, with a unique mood and a name day celebrated in Estonia.
| Country | Day | Month | Names |
 USA | 7 | January | Alda, Aldea, Alden, Aldo, Aldric, Canute, Knut, Knute, Millard, Miller |
 Spain | 11 | January | Alejandro, Guillermo, Hortensia, Higinia, Higinio, Modesto |
| USA | 14 | January | Alair, Felice, Felicia, Felicity, Felix, Hilary, Hillary, Hillery |
| Spain | 10 | February | Guillermo, Amancio, Arnaldo, Arnau, Ecolástica |
| USA | 23 | February | Boswell, Gloria, Gloriana, Glory, Reilley, Riley, Rylan, Rylee, Ryleigh, Ryley, Rylie |
 France | 18 | March | Cyrille |
 Estonia | 30 | March | Pille, Sibülle |
| Estonia | 6 | April | Villem, Ville, Villi, Villo, Villu |
 Finland | 6 | April | Ville, Vilho, Viljami, Jami, Vilhelm, Vili |
 Greece | 24 | April | Elizabeth, Lisa, Anastasios, Doukas, Achilles, Orthodox Easter |
| France | 7 | May | Domitille, Gisèle |
| France | 12 | May | Achille |
| USA | 12 | May | Achilla, Achilles, Grady, Grant, Kelby, Kellen |
| Estonia | 20 | May | Liilia, Lilian, Liili, Lille, Lilli, Lilja |
| France | 31 | May | Pétronille |
 Norway | 31 | May | Pernille, Preben |
| USA | 31 | May | Camila, Camilla, Camille, Petra, Petronella, Pier |
| Spain | 25 | June | Salomón, Guillermo |
| USA | 25 | June | Bill, Billie, Billy, Guillermo, Liam, Mina, Minnie, Prosper, Velma, Vilma, Wilhelmina, Will, William, Willie, Willis, Wilma, Wilson |
 Denmark | 7 | July | Henrik, Villebaldus |
| France | 14 | July | Camille |
 Hungary | 20 | July | Illés |
| France | 22 | July | Madeleine, Wandrille |
| USA | 6 | August | Adriel, Araceli, Falco, Falcon, Itzel, Lucia, Lucille, Lucine, Lucy, Luz |
| France | 1 | September | Gilles, Jossué |
| Denmark | 11 | September | Hillebert |
| Finland | 16 | September | Hilla, Hellevi, Hille, Hillevi |
| France | 3 | October | Gérard, Sybille |
 Sweden | 15 | October | Hedvig, Hillevi |
| Hungary | 2 | November | Achilles |
| France | 6 | November | Bertille, Léonard |
 Poland | 7 | November | Achilles, Antoni, Engelbert, Florentyn, Melchior, Przemił |
 Austria | 8 | November | Gottfried, Willehad |
| Sweden | 18 | November | Lillemor, Moa |
| Estonia | 22 | November | Cecilia, Säsil, Silja, Silje, Sille |
| USA | 17 | December | Eleazar, Lazar, Lazaro, Lazarus, Olympia, Orval, Orville, Storm, Stormie, Stormy, Wilbert, Wilberta, Wilbur |