Exploring the Great Migration – 1910-1970 United States Census Bureau | An official website of the United States Government An official website of the United States government Here’s how you know Here’s how you know Official websites use .gov A .gov website belongs to an official government organization in the United States. Secure .gov websites use HTTPS A lock ( Lock A locked padlock ) or https: Topics: The Great Migration during the 20th century Population. Topics: The Great Migration during the 20th century Population.