According to reports from the Hmong and Somali communities, Minnesota is home to the largest Hmong and the largest Somali population in the United States.
http://www.mnadvocates.org/Minnesota%E2%80%99s_Immigrant_Populations___Past_and_Present.html
This is from 2002 but I have always read that we (Mpls) have the largest Somali population.
Was at the Mall of America earlier this month and was struck by how many veiled women were serving as janitors.
If I remember correctly, Minneapolis has a pretty big mall.