South Dakota

For American Indians on the Cheyenne River Indian Reservation in South Dakota, getting health care can take weeks. Indians who move to the city find that access can be difficult, too.

Hold out your hand for a century, and 100 million particles of dark matter will pass through each second without leaving a trace. Still, a physicist in South Dakota thinks he may be able to catch one.

President Obama's visit to South Dakota will allow him to brag that he has set foot in each of the 50 states — only three other U.S. presidents can make that claim.

Where have the insurance marketplaces created by the Affordable Care Act struggled the most? The answer lies in commerce, not politics.