Arianna hits D.C. starting today.

Two former DCist editors launched new projects today that are certainly worth a visit.

Co-founder Mike Grass is heading up the Huffington Post’s local D.C. site, joining a number of existing city-centric off-shoots of the massive media outlet. As Arianna Huffington herself wrote by way of introduction, the site will focus on the two sides of D.C. — the federal and the local — and the great divide that often exists between the two.

DCist’s most recent former editor-in-chief, on the other hand, is spearheading The Atlantic Cities, a site dedicated to, well, all things city. Sommer Mathis explains:

First, we want to offer reported features that tell great stories about where cities are today, where they’ve been, and where they’re heading. Second, we want to deliver short, authoritative takes on the latest news and events happening in cities across the globe. Third, we want to gather the smartest thinkers and researchers in urbanism, anchored by the innovative work of Atlantic senior editor and Atlantic Cities godfather Richard Florida, to facilitate a bigger-picture, ideas-based conversation with our readers. And fourth, we want to use a variety of media, from charts and maps to photos, video and text, to tell these stories.

So head on over to both sites and say hi.