The workers are being aided by area food banks and resort officials, The (Flagstaff) Arizona Daily Sun reported Tuesday.
The closure of the park during the federal government shutdown has had a "devastating" effect on workers, said Jerry Brown, a spokesman for St. Mary's Food in Phoenix that delivered 600 boxes of food to the park Tuesday.
About 2,200 people are still inside the park, about 1,800 of them employees of resorts and other concessionaires.
Some of those employees work for Forever Resorts, which operates a concession on the North Rim that wasn't scheduled to close for two weeks.
"We're trying to help them as much as we can, but our revenue is struggling too," said Scott Gold, the company's regional vice president.
One employee contacted the company because he couldn't afford to leave the park and find work elsewhere.
"He said 'I don't know what to do. I have less than $100. I was relying on my last week's pay to get out of here,'" Gold said of the worker.
Forever Resorts announced Monday it was losing $250,000 a day because of the shutdown.
The park's largest contractor, Xanterra, says it continues to feed its employees three meals a day, but only one meal a day to workers' families. Other park employers don't provide any food to their workers.
St. Mary's said it plans to continue providing food through next week, but Brown said it's running low on supplies too.