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Noah Berger, Associated Press
In this June 4, 2015 photo, tech workers from Whil, a start-up company providing digital platforms to improve health, confer at the 1920c workspace in San Francisco's Chinatown. 1920c, a fledgling co-sharing business launched in April, offers work space to freelancers and to socially conscious startups.

SAN FRANCISCO — For a century and a half, San Francisco's Chinatown, the nation's oldest, has sheltered waves of immigrants seeking a new life.

It's the birthplace of Chinese America, and to some extent, the broader Asian America that descended from immigration over the Pacific Ocean throughout the 19th and 20th centuries.

Now, Chinatown faces economic and demographic challenges that could upend its identity as the city undergoes an unprecedented growth in jobs.

Rising rent elsewhere has entrepreneurs eyeing Chinatown for space. At the same time, longtime leaders want ways to attract younger people. And depending on who is talking, a $1.6 billion subway set to open in 2019 could help or hurt the district's transformation.

Chinatown leaders want the district to be a gateway for immigrants and destination for tourists. But some wonder if the birthplace of Chinese America can maintain its heart amid the race for space.