Trump has promised "a big, attractive wall" with Mexico as a centerpiece of his presidency but offered few details of where it would be built, when and at what cost.
The administration asked lawmakers for $18bn in order to add 316 miles of walls and fencing along the border and bolster 407 miles of existing barriers, according to a financial blueprint sent to senators by US Customs and Border Protection on Friday.
The Customs and Border Protection document calls for a total of $33 billion in new border spending, including $18 billion for the wall, $5.7 billion for technology gear, $1 billion for road construction and maintenance and $8.5 billion for 5,000 new Border Patrol agents, 2,500 border inspectors and other personnel, the USA official said.
Trump has demanded a border wall in exchange for passing legislation that would shield from deportation hundreds of thousands of young migrants brought to the USA as children, known as Dreamers.
In return for the cash, the Trump administration will be expected to discuss a way forward for the so-called dreamers - illegal immigrants who were brought to the United States by their parents and know no other country.
At Camp David, Trump convened his cabinet and Republican leaders to discuss, among a laundry list of legislative priorities, immigration.
"We want DACA to happen", Trump said Saturday. So we have to get rid of the lottery system.
The subject came up during a sit-down meeting with GOP lawmakers at the White House on Thursday.
So the funds Trump seeks from Congress would be enough to say that by 2027, just over half the border is walled off.
The episode prompted a shutdown warning from Durbin, with government funding scheduled to run out January 19 and a long-term budget will require Democratic votes.