Racial Diversity by County

The Atlantic:

Each county has a breakdown of ethnicities by percentage—i.e., Montgomery County, Maryland, is 49.3 percent white, 16.6 percent black, 0.2 percent Native American, 13.9 percent Asian, 17 percent Latino, and 3.1 percent "other." Olson quantified diversity by calculating entropy for each of these sets. He explains it on his blog like this: "A county will come out with high entropy when all six ethnic categories are as even as possible (i.e., each ~16.7 percent), whereas it will come out with low entropy if the county is only inhabited by people of one ethnic category."...
The 5 most diverse counties in the U.S., according to Olson's calculations, are:

1. Aleutians West Census Area, Alaska (31.4 percent white/non-Latino, 5.7 percent African American, 15.1 percent Native American, 28.3 percent Asian American, 13.1 percent Latino, and 6.4 percent other)
2. Aleutians East Borough, Alaska (13.5 percent white/non-Latino), 6.7 percent African American, 27.7 percent Native American, 35.4 percent Asian American, 12.3 percent Latino, and 4.4 percent other)
3. Queens County, New York (27.6 percent white/non-Latino, 17.7 percent African American, 0.3 percent Native American, 22.8 percent Asian American, 27.5 percent Latino, and 4 percent other)
4. Alameda County, California (34.1percent white/non-Latino, 12.2 percent African American, 0.3 percent Native American, 25.9 percent Asian American, 22.5 percent Latino, and 5.1 percent other)
5. Solano County, California (40.8 percent white/non-Latino, 14.2 percent African American, 0.5% Native American, 14.3 percent Asian American, 24 percent Latino, and 6.2 percent other)

And the 5 least diverse:

1. Tucker County, West Virginia (100 percent white/non-Latino)
2. Robertson County, Kentucky (100 percent white/non-Latino)
3. Hooker County, Nebraska (100 percent white/non-Latino)
4. Hand County, South Dakota (99 percent white/non-Latino and 1 percent Latino)
5. Owsley County, Kentucky (98 percent white/non-Latino and 2 percent Latino)

As to what surprised Olson the most? "As a Michigander," he writes, "I’m the most surprised to see how diverse the Upper Peninsula is. I thought only crazy white people lived up that far in Michigan."

Two words about the U.P.: Indian casinos.  I am surprised that Mercer County, Ohio can't break into the 5 least diverse counties.