Obama, in a briefing to reporters, said he did not expect the United States to have to stage an evacuation of the mountain, where thousands of members of the Yazidi religious minority had been trapped by militants, or to continue humanitarian airdrops.
"We broke the ISIL (Islamic State of Iraq and the Levant) siege of Mt Sinjar," Obama said.
"We helped innocent people reach safety and we helped save many innocent lives. Because of these efforts we do not expect there to be an additional operation to evacuate people off the mountain and it's unlikely that we are going to need to continue humanitarian airdrops on the mountain.
"The majority of the military personnel who conducted the assessment will be leaving Iraq in the coming days," he said.
The United States had sent about 130 US military personnel to Arbil to draw up options ranging from creating a safe corridor for the Yazidis to an airlift to rescue them. A team of fewer than 20 US personnel flew to Mt Sinjar to assess the situation.
Obama said the United States would continue airstrikes to protect US facilities in Iraq and called on Iraqis to unite to defeat Islamist insurgents.