The mansions of the Elder King, Manwë, and his spouse Varda Elentári, on the peak of Taniquetil. Ilmarin is translated as 'mansion of the high airs', an appropriate name for a dwelling-place built on the tallest peak of all the mountains in the world. The birds, servants and allies of Manwë, were said to travel to and from Ilmarin bringing news from the outer world.
Though the name Ilmarin properly refers to the dwellings of Manwë and Varda, it seems at times to be used as a poetic name for Taniquetil itself. For example, in The Fellowship of the Ring II 8 (Farewell to Lórien), Galadriel sings of the 'strand of Ilmarin'. A 'strand' is a shoreline, so she cannot mean this literally - instead, she seems to be describing the seaward lands beneath the mountain on which Ilmarin stood.