Mia

Also Latvian: https://personvardi.pmlp.gov.lv/index.php?name=Mia

Also Czech: https://cs.m.wikipedia.org/wiki/Mia

Also Estonian: https://www.stat.ee/nimed/Mia

Also Romansh:
Source: "Vornamen in der Schweiz. Prénoms en Suisse. I nomi in Svizzera. Prenoms in Svizra" (1993) published by the Association of Swiss registrars
Https://nossaistorgia.ch/entries/nBLD8BL0ZA8
Https://nossaistorgia.ch/entries/rmyDrAe8V8R
Https://www.portraitarchiv.ch/portrait?page=343

Also Hungarian: https://hu.wikipedia.org/wiki/M%C3%A1ria -- mention Mia as a short form

Mia (Μία) also means "one" in Greek.

Also used in Slovene: https://sl.wikipedia.org/wiki/Mia [noted -ed]

Also used in Estonia: https://et.wikipedia.org/wiki/Mia_(eesnimi)
https://www.stat.ee/public/apps/nimed/

Mia is also used as a short form of Amelia.

Mia has recently become trendy in Poland. It was unheard of before.

In 2018, 4 is the most common age for an American (U.S.) Mia who is registered female with the Social Security Administration. It is the 462nd most common female first name for living U.S. citizens.

Also short for Miranda, Madelina, Emilia, Mila, Milena.

Also used in Hungary. Pronounced: MI-aw.

Also a popular girls name in Croatia for the last 30 years.

Mia is also used in Finland, though it isn't quite as popular as the form Miia. Here it's pronounced MEE-ah.

This name is also very common in Limburgish, where it is a short form rather than a diminutive of Maria.

Mia is also commonly used in the Netherlands as a pet form of Maria. [noted -ed]

Also a girls name in Slovenia.

Mia is very poular in Norway. [noted -ed]

Mia has recently become extremely popular with Hispanics in the USA because of a telenovela called _Rebelde_, which featured the very popular young Mexican actress Anahi in the role of Mia Colucci.

The name Mia Colucci that clevelandkentevans mentioned previously was also used for the same character in the original version of "Rebelde" made in Argentina that was called "Rebelde Way". The character was played by Luisana Lopilato.