San Francisco is 19% larger than Montserrat.
Area: 102 km2 World Factbook
Population: 5,215 (July 2014) World Factbook
Montserrat is a British Overseas Territory located in the Caribbean. The island is located in the Leeward Islands, part of the chain of islands known as the Lesser Antilles, in the West Indies. Wikipedia
Area: 122 km2 calculated
San Francisco, officially the City and County of San Francisco, is the cultural center and a leading financial hub of the San Francisco Bay Area and Northern California. Wikipedia