What are the parts of a mosque?

The main parts of a mosque are the prayer hall, the mihrab, the minbar, the wudu area and, in many mosques, a minaret and dome. Only the prayer hall is really needed. The rest grew up over centuries to make praying together easier.

The prayer hall

The heart of every mosque is the prayer hall (musalla or main hall), usually a large carpeted space without chairs or pews. The carpet often has lines or patterns that help people stand in straight rows. Everyone faces one wall, the qibla wall, which points toward the Kaaba in Mecca. See Why do Muslims pray facing Mecca?

The Quran describes these houses of worship beautifully:

فِى بُيُوتٍ أَذِنَ ٱللَّهُ أَن تُرْفَعَ وَيُذْكَرَ فِيهَا ٱسْمُهُۥ "[Such niches are] in houses which Allah has ordered to be raised and that His name be mentioned therein..." Quran 24:36

Mihrab and minbar

Mihrab: a niche or arch in the qibla wall. It shows the direction of prayer, and the imam stands in front of it when leading.
Minbar: a raised pulpit with a few steps, to the right of the mihrab. The imam gives the Friday sermon (khutbah) from it. The Prophet ﷺ first gave sermons leaning on a palm trunk; later a simple wooden minbar of three steps was made for him. See Can the Friday khutbah be in English?

Wudu area, shoe racks and the women's section

Wudu area: rows of low taps with seats, where people wash before prayer. Many have separate ones for men and women.
Shoe racks: shoes come off before the carpet, so there's always a shoe area at the entrance.
Women's area: some mosques have women praying behind the men in the same hall; others use a balcony or separate room. See Can women pray in the main hall of the mosque?

Minaret, dome and courtyard

A minaret is a tower once used to call the adhan from a height so the whole town could hear. A dome covers the main hall in many mosques and helps the voice carry. A courtyard (sahn), often with a fountain, is common in hot countries. None of these are required: the Prophet's ﷺ own mosque in Madinah had none of them at first. Many Western mosques are converted buildings without any of them, and they're just as much a mosque.

Other rooms you'll often find

Larger mosques also have classrooms, a library with copies of the Quran, an office, a kitchen for community meals, and a room for washing the dead before funerals. Before your first visit, check What should I wear to the mosque?

Key points

The prayer hall faces the qibla wall toward Mecca.
The mihrab marks the direction; the minbar is for the sermon.
Wudu areas and shoe racks are found in almost every mosque.
Domes and minarets are traditional but not required.

Tip: On your first visit, look for the mihrab to find the qibla, and use the shoe rack before stepping on the carpet. If you're unsure where the sisters' entrance or wudu area is, just ask; people are usually glad to help.