The terror group now has a very tiny sliver of land along the banks of the Euphrates River under its control.
The frontline was quiet on Thursday, for the second-day in a row, as the SDF paused its push to allow for more surrenders.
"We have won. We have eliminated the enemy, the terrorists", Majid Hejjo, an SDF fighter, told the French news agency.
SDF official Jiaker Amed said Thursday that several ISIS fighters were still in hiding.
Before President Donald Trump left the White House to visit OH, he brought out a map to show reporters how much territory ISIS has lost since election day in 2016.
Trump later showed off the maps on his Twitter handle comparing the territory ISIS seized before his election in 2016, and the small portion the terrorist group now occupied. "In fact, there´s actually a tiny spot which will be gone by tonight", he said at the White House.
Still, SDF officials and US defense officials have been wary of saying the fight against the terror group's self-declared caliphate is over.
The ISIS caliphate is conquered, as the final stronghold of the empire that once ruled over 8 million is liberated, Fox News has learned. But even after Baghouz's fall, IS maintains a scattered presence and sleeper cells that threaten a continuing insurgency. This just came out 20 minutes ago. In recent days, as the enclave shrank, the SDF said hundreds more of them started to surrender, or were captured trying to escape.
For the past four years, US-led forces have waged a destructive campaign against the group.
There was no immediate update from the SDF on Wednesday on the fate of these remaining militants.
Thousands of SDF troops have massed around Baghuz for weeks, laying siege to the town in an effort to liberate the final IS enclave in Syria.
A clearing operation is now underway and an official announcement is expected soon.
US military officials have confirmed a residual force of 400 troops will be split between northeastern Syria and the southern part of the country.
The United States believes Iraq is the location of its leader Abu Bakr al-Baghdadi, who stood at the pulpit of the great medieval mosque in Mosul in 2014 to declare himself caliph, sovereign over all Muslims.