The Huffington Post has hired a staffer for a Denver site. The site, in the nation’s 20th largest market, will be HuffPo’s third local site when it launches in September. New York and Chicago are already up.

Los Angeles is slated to be No. 4, with more than a dozen sites planned in all. The sites are being linked with other local media, such as ESPNLocal, and typically will have one or two editors per market.

The Denver editor is Ethan Axelrod, the son of David Axelrod (a top Obama administration official). “I’ve been interested in journalism for a while,” the 22-year-old graduate of Colorado College told Howard Kurtz of The Washington Post. “I heard through my father that they were expanding, so I applied for it.”

Axelrod won the job after submitting a mockup of the Denver home page and interviewing with Arianna Huffington.