Donald E. Graham speaks at a 2014 DC-CAP event celebrating students’ graduation from college. (Sarah L. Voisin/The Washington Post)

TheDream.US, the nation’s largest scholarship fund for immigrant youths who entered the country illegally as children, is embarking on a campaign to raise at least $30 million to help undocumented students pay for college.

Donald E. Graham, a former owner of The Washington Post who co-founded TheDream.US last year, has pledged $15 million to kick off the fundraising drive, as has hedge fund manager Bill Ackman. Their gifts were in addition to previous donations of $10 million each and were meant in part to spur other philanthropists to donate.

The money will go toward providing $25,000 scholarships to undocumented students who have filed for temporary legal status. They may use the money to attend preapproved U.S. schools for higher education that otherwise would have been out of reach.

Each year, an estimated 65,000 undocumented students, often called “dreamers,” graduate from U.S. high schools. But they are not eligible for federal Pell grants and other types of federal financial aid that make college more affordable.

“How can we change the world? I will be betting on dreamers,” Graham said this month at the City University of New York, where more than 300 students have been awarded TheDream.US scholarships.

Graham previously founded the District of Columbia College Access Program, which has helped thousands of D.C. students get into and pay for college. He co-founded TheDream.US in early 2014, after his company sold The Post to founder Jeffrey P. Bezos.

TheDream.US officials said the organization has raised $81 million since its inception and has awarded scholarships to about 1,000 students.