Congress failed come up with an agreement to fund the federal government in time to meet its Tuesday deadline. The impact of a government shutdown will depend on how long it lasts.
Along the southern border, the ports of entry will remain staffed and open. The federal courts will continue criminal and immigration cases, but civil cases will be postponed. Federal law enforcement and the military will also remain on duty.
But hundreds of thousands of federal employees might not get a paycheck.
"All those folks have families, they have mortgages to pay," said Sen. Martin Heinrich (D-N.M).
With two national laboratories and four military bases, New Mexico is among the states most dependent on federal jobs. One third of the state's GDP is dependant on federal dollars.
National Parks across the Southwest, like the Grand Canyon, will also close starting Tuesday.
"If I'm an interpretive ranger at Big Bend and I'm not on the list of essential personal, I go home," said Patrick O'Driscoll, a spokesman for the National Parks Service.
A prolonged shutdown could eventually reduce federal funds for government contracts, university research and even school lunches.