Borujerd sits in the Silakhor plain of western Iran, with the Zagros Mountains close enough to make the horizon feel high. It is not one of Iran's polished showpiece cities, but it has a real old-city core and enough architectural weight to reward a stop between Tehran, Hamadan, and Khorramabad.
The best reason to come is the cluster of historic religious buildings around the centre. The Jameh Mosque goes back to the early Islamic period and is often described as the oldest mosque in western Iran. Nearby, the Qajar-era Soltani Mosque gives the city a later, grander face, while Imamzadeh Jafar preserves one of the region's clearest Seljuk forms.
Borujerd also feels distinctly Lorestan. The bazaar still serves Lur and Persian-speaking villages from the surrounding countryside, and the hills west of town make an easy escape when the city gets dusty. Come for a spare day if you are already crossing western Iran; do not detour across the country for it.