The name day associated with Ilia is observed on August 2nd in Poland.
The name Ilia is globally recognized as a masculine identifier, stemming from a traditional Slavic origin meaning "the Lord is my God." In the USA, it is moderately utilized, often reflecting Eastern European cultural heritage while maintaining a classic, distinct feel. The history of Ilia is closely tied to Orthodox Christian traditions across Russia and the Balkans. This strong background contributes to the name's quiet yet elegant mood and sophisticated tone. Its pronunciation is easily accepted in the American context, lending it an international flair.
| Country | Day | Month | Names |
 Spain | 3 | January | Daniel, Genova, Genoveva, Jennifer, Florencio, Prisciliano |
 Austria | 5 | January | Emilia, Johann |
 Poland | 5 | January | Edward, Emilian, Emiliusz, Hanna, Symeon, Szymon, Telesfor, Włościbor |
| Spain | 5 | January | Amada, Simón, Simona, Emiliana |
 Sweden | 1 | February | Max, Maximilian |
 Italy | 9 | February | Girolamo Emiliani |
 Lithuania | 14 | February | Liliana, Saile, Saulius, Valentinas |
| Poland | 14 | February | Adolf, Adolfa, Adolfina, Alf, Cyryl, Dobiesława, Dobisława, Józef, Józefa, Konrad, Konrada, Krystyna, Lilian, Liliana, Mikołaj, Niemir, Niemira, Walenty, Zenon, Zenona |
 Czechia | 25 | February | Liliana |
 Latvia | 10 | March | Adrians, Kira, Laimrota, Liliana, Silvija |
| Spain | 12 | March | Josefina, Maximiliano, Fina |
| Italy | 13 | March | Massimiliano |
| Austria | 21 | March | Axel, Christian, Emilia |
| Spain | 27 | March | Ruperto, Lilia, Alejandro |
| Spain | 5 | April | Emilia, Vicente Ferrer |
| Sweden | 9 | April | Ottilia, Otto |
| Latvia | 30 | April | Liana, Liliana, Lilija, Linda |
| Austria | 10 | May | Gordian, Isidor, Liliana |
 USA | 10 | May | Cormac, Cormick, Gordon, Job, Joby, Jobina, Max, Maximilian, Maximus, Maxine, Maxwell |
 Finland | 19 | May | Emilia, Emma, Mila, Milena, Amalia, Emmi, Milja, Milka, Milla, Amelia |
 Estonia | 20 | May | Liilia, Lilian, Liili, Lille, Lilli, Lilja |
| Finland | 20 | May | Lilian, Lilja, Karoliina, Lila, Lili, Lilli, Lilia |
| Poland | 23 | May | Budziwoj, Dezyderiusz, Dezydery, Emilia, Iwona, Jan, Leontyna, Michał, Symeon |
| Spain | 24 | May | Rocío, Susana, Auxiliadora, Providencia, Ester |
 Slovakia | 28 | May | Viliam |
| USA | 28 | May | Bevan, Bevis, Emil, Emiliano, Emilio, Faron, Ferrin, Ferron |
| Czechia | 29 | May | Maxmilián |
| Poland | 29 | May | Bogusława, Maksymilian, Maria Magdalena, Teodor, Teodozja |
 Bulgaria | 30 | May | Emiliya, Emil, Emilia, Emilian, Emiliana |
 Hungary | 3 | June | Klotild, Cecília |
| USA | 14 | June | Basil, Basilia, Jaren, Jaron, Jarron, Vasily |
| Poland | 24 | June | Dan, Danisz, Danuta, Emilia, Jan, Wilhelm |
| Poland | 30 | June | Alpinian, Ciechosława, Cyryl, Emilia, Lucyna, Marcjal |
| Austria | 8 | July | Amalia, Edgar, Kilian |
| Poland | 8 | July | Adrian, Adrianna, Chwalimir, Edgar, Elżbieta, Eugeniusz, Kilian, Prokop, Wirginia |
| USA | 8 | July | Aquila, Aquilina, Easton, Kilian |
| Bulgaria | 18 | July | Emil, Emilian, Emilia, Emiliyana |
 Greece | 18 | July | Emilianos, Emily |
| Spain | 18 | July | Emiliano, Federico, Luz |
| Hungary | 19 | July | Emília |
| Hungary | 27 | July | Olga, Liliána |
| USA | 27 | July | Joy, Joyce, Lila, Lilac, Liliana, Lillian, Lillie, Lilly, Lily |
| Poland | 31 | July | Beatus, Demokryt, Emilian, Ernesta, Ernestyna, Helena, Iga, Ignacja, Ignacy, Justyn, Ludomir, Żegota |
| Greece | 4 | August | Maximilian |
| Bulgaria | 8 | August | Emil, Emilian, Emiliya, Emilia, Trendafil |
| Poland | 8 | August | Cyprian, Cyriak, Cyryl, Emil, Emilian, Emiliusz, Niezamysł, Olech, Sylwiusz |
 Ukraine | 8 | August | Amelia, Amilian, Emil, Emily, Fedir, Theodore, Leonid |
| Austria | 14 | August | Maximilian, Meinhard |
| USA | 18 | August | Aileen, Eileen, Elaina, Elaine, Eleanor, Elena, Eliana, Ella, Elle, Ellen, Ellie, Helen, Helena, Iliana, Lena, Leonora, Nell, Nellie, Nelly |
| Poland | 19 | August | Bolesław, Emilia, Jan, Julian, Juliusz, Ludwik, Piotr, Sebald |
| Austria | 21 | August | Maximilian, Pius |
| Poland | 21 | August | Adolf, Adolfa, Adolfina, Alf, Bernard, Emilian, Filipina, Franciszek, Joanna, Kazimiera, Męcimir |
| Poland | 4 | September | Agatonik, Ida, Lilianna, Rościgniew, Róża, Rozalia |
| Sweden | 6 | September | Lilian, Lilly |
| Greece | 13 | September | Kornilios, Kornilia, Aristeides |
| Poland | 11 | October | Aldona, Brunon, Burchard, Dobromiła, Emil, Emilian, Emiliusz, Germanik, Maria, Marian, Placydia |
| Austria | 12 | October | Edwin, Gottfried, Maximilian |
 Denmark | 12 | October | Maximilian |
 Germany | 12 | October | Maximilian |
| Poland | 12 | October | Cyriak, Eustachiusz, Eustachy, Grzymisław, Maksymilian, Ostap, Salwin, Serafin, Witold, Witołd, Witolda |
| Slovakia | 12 | October | Maximilián |
| Lithuania | 21 | October | Gilinda, Hiliaras, Raitvilas, Ursule |
| Bulgaria | 8 | November | Angel, Angelina, Arhangel, Gavrail, Gavril, Emil, Emilia, Emiliana, Mihaela, Mihail, Ognyan, Ognyana, Plamen, Plamena, Rada, Radka, Radko, Rafail, Raia, Raika, Raina, Rangel, Emiliya, Emiliyana, Emiliyan, Lina, Mila, Milen, Milyo, Mihaela, Mihail, Radivoy, Radoslav, Radoslava, Radostin, Radostina, Raiko, Raycho, Rangel, Rafail, Raya, Rusi |
| Sweden | 14 | November | Emil, Emilia |
| Austria | 22 | November | Cäcilia, Salvator |
| Denmark | 22 | November | Cecilia |
| Estonia | 22 | November | Cecilia, Säsil, Silja, Silje, Sille |
| Finland | 22 | November | Selja, Silja, Seela, Cecilia |
| Greece | 22 | November | Filimonos, Cecilia |
| Hungary | 22 | November | Cecília |
| Italy | 22 | November | Cecilia |
| Slovakia | 22 | November | Cecília |
| Spain | 22 | November | Cecilia |
| Sweden | 22 | November | Cecilia, Sissela |
| USA | 22 | November | Abbey, Abbie, Abby, Abigail, Cecelia, Cecil, Cecilia, Cecily, Cecyl, Celia, Gael, Gail, Galen, Gay, Gayle, Philemon, Philo, Shayla, Sheila |
| Poland | 24 | November | Dobrosław, Emilia, Emma, Flora, Franciszek, Gerard, Gerarda, Gerhard, Jan, Mina, Pęcisław, Protazy |
| Slovakia | 24 | November | Emília |
| Greece | 26 | November | Stilianos, Stella, Stelios |
| Poland | 27 | November | Damazy, Dominik, Leonard, Maksymilian, Oda, Stojgniew, Walery, Wirgiliusz |
| USA | 27 | November | Fergus, Farrel, Farrell, Ferrell, Ginger, Virgil, Virgilia, Virginia |
| Poland | 6 | December | Dionizja, Emilian, Jarema, Jarogniew, Mikołaj |
| USA | 10 | December | Emely, Emilee, Emilia, Emilie, Emily, Eula, Eulalia, Ula |
| Slovakia | 12 | December | Otília |
| Austria | 13 | December | Jodok, Lucia, Odilia |
| Hungary | 13 | December | Luca, Otília |