Cosmopolis is a city in Grays Harbor County, Washington, United States. The population was 1,649 at the 2010 census. Take a look below for 15 interesting and awesome facts about Cosmopolis, Washington, United States. 1. Cosmopolis is located at 46°57′19″N 123°46′23″W (46.955352, -123.773176). 2. According to the United States Census Bureau, the city has a…