The Colonial Building is a historic government building located in St. John's, Newfoundland and Labrador, Canada. The building was the home of the colonial and later provincial Newfoundland government and the House of Assembly from January 28, 1850 to July 28, 1959. In 1974, it was declared a Provincial Historic Site. On May 24, 1847, the cornerstone was laid by the Governor, Major-General Sir John Gaspar Le Marchant. The official opening of the Colonial Building took place on January 28, 1850, by Governor Le Marchant for the second session of the House's fourth general assembly.