Samantha Power, chief of the U.S. Agency for International Development (USAID), announced the new assistance on a visit to Chad, which before the latest fighting was already the host of some 600,000 refugees, mostly from Sudan.
USAID said it was committing $50 million to address needs inside Sudan as well as $22 million for South Sudan, $17 million for Chad and $6 million for Egypt.
In Chad, the assistance will go through the U.N.'s World Food Program to provide food and cash assistance to more than 135,000 people, including newly arrived refugees from Sudan.
USAID noted that Chad was already "stretched thin." South Sudan has been coping with its own internal humanitarian disaster, along with masses of Sudan refugees.
"The conflict in Sudan forces humanitarian partners across the region to make difficult choices about how to address compounding needs with limited resources," a USAID statement said.
"The United States urges other donors to help us address critical funding gaps."
The United Nations said Wednesday that $3.03 billion would be needed to provide urgent aid for Sudan as well as for the more than one million people expected to flee into neighboring countries this year.
Sudan descended into war on April 15 in a conflict between the army and a powerful paramilitary unit as they rejected a plan to merge under a promised transition to civilian rule.
The United States and Saudi Arabia have been leading mediation in hopes of reaching another at least temporary ceasefire to allow in assistance.