Washington-ArlingtonAlexandria, DC-VA-MD-WV

Amazon’s plopping half of its new outpost in Crystal City, Virginia, will create opportunities—and challenges, particularly for businesses competing with the tech giant for talent. Virginia Tech’s promise of a new $1 billion innovation campus will help. Cybersecurity is among the most vibrant ecosystems here, with many startups staffed by former NSAers. One star is Appian, a cloud software firm whose decision— post IPO—to stay local and add 600 jobs buoyed boosters of the thriving Dulles Tech Corridor. Edtech is surging, with online course provider EverFi raking in $251 million in funding. And a unicorn was born when under-the-radar A.I. company Afiniti raised $130 million on a valuation of $1.6 billion.