Kalgoorlie Boulder known colloquially as just Kalgoorlie is a city in the Goldfields Esperance region of Western Australia located 595 km 370 mi east northeast of Perth at the end of the Great Eastern Highway The city was founded in 1889 by the amalgamation of the towns of Kalgoorlie and Boulder which developed in 1893 during the Coolgardie gold rush on Western Australia s Golden Mile