The city was built on the great Plain of Valinor beyond the shield of the Pelóri, gated with great golden gates. It had silver domes, and streets paved with gold. Before the city's western gate lay the mound of Ezellohar, on which stood the Two Trees, and Máhanaxar, the Ring of Doom, were outside Valmar. Valmar is generally considered the capital of Valinor, as it was there that the Valar congregated.
After being released from prison, Melkor lived here for a time as he could not leave the city due to the Valar's mistrust of him.
Tolkien may have based Valmar off of the City of Heaven, from the christian religion, as the cities structures, streets and gates are very similar towards the structures, streets and gates mentioned of the city of heaven in the bible.