Some of the biggest names in American philanthropy have joined forces to spend at least $500 million over five years to revitalize the coverage of local news in places where it has waned.

Led by the Chicago-based MacArthur Foundation, the new initiative, called Press Forward, seeks to nurture and sustain new models for funding journalism as the industry has come under severe financial pressures. In its announcement Thursday, the group of more than 20 charitable organizations noted that about a fifth of the nation live in so-called “news deserts” with little or no reliable coverage of major local developments.