The current Apple campus in Austin, Tex. The company is planning a new 133-acre campus there that will initially have 5,000 workers. Tamir Kalifa for The New York Times

SAN FRANCISCO — This generation’s biggest technology companies — including Apple, Amazon and Google — have long been tied to their hometowns. Now these giants are increasingly outgrowing their West Coast roots.

Driven by a limited pool of skilled workers and the ballooning cost of living in their home bases of Silicon Valley and Seattle, as well as President Trump’s shifting immigration policies, the companies are aggressively taking their talent hunt across the United States and elsewhere. And they are coalescing particularly around a handful of urban areas that are already winners in the new knowledge-based economy, including New York City, Washington, Boston and Austin, Tex.

This eastward expansion accelerated on Thursday when Apple said it would build a $1 billion campus in Austin, expanding its presence there to over 11,000 workers and becoming the area’s largest private employer. The decision followed Amazon’s highly publicized selection of Queens and Arlington, Va., last month for new offices that would house at least 50,000 employees. Google, too, is shopping for more real estate in New York that could enable it to more than double its work force of 7,000 in the city.

“They’re expanding out,” said Mark Zandi, chief economist at…