More than $2.5 billion has been released after being frozen due to lawsuits.
The funding will go into repairs of fencing and future wall building.
Trump will now be closer to fulfilling his 2016 campaign promise.
The US Supreme Court has cleared the way for the Trump administration to use billions of dollars in Pentagon funds to build sections of a border wall with Mexico.
The court’s five conservative justices gave the administration the green light to begin work on four contracts it has awarded using Defense Department money.