President Trump is taking on defiant sanctuary cities as he seeks to fulfill a vital campaign pledge to mass deport illegal immigrants while blue city leaders dig in their heels, resisting any form of assistance to federal authorities that could lead to migrants’ removal. 

Tom Homan, Trump’s designated border czar, has promised to unveil a series of “game-changing” executive orders that have prompted sanctuary cities to cement their statuses as safe havens for migrants.

The cities, from Chicago to San Diego, have doubled down by reaffirming local ordinances to prohibit local law enforcement from assisting federal authorities in immigration removal operations.

President Trump put illegal immigration front and center in his inaugural address on Monday, promising: “All illegal entry will immediately be halted, and we will begin the process of returning millions and millions of criminal aliens back to the places from which they came.” 

While there are key sanctuary cities that are intent on dissuading Trump’s policy plan, there are pockets of cities and states intent on assisting Trump.

In Colorado, Douglas County’s board of commissioners approved a resolution in support of Trump’s mass deportation plan. The unanimous vote confirmed the county, which is neighboring the sanctuary city of Denver, as a “non-sanctuary county.”

“We are going to follow and adhere to federal immigration law,” Douglas County Chairperson Abe Laydon told Fox News Digital. “We will continue to support the U.S. Constitution and follow federal immigration law.”

“We want to empower our local law enforcement, our sheriff’s office, and communicate with federal immigration officials, to get information and keep people safe in our community,” he said. “The three of us, as the board of county commissioners, are going to hold the line in Douglas County and ensure that our community stays safe.”

Migrants, many from Haiti, are seen at an encampment along the Del Rio International Bridge in Del Rio, Texas.  (AP Photo/Julio Cortez)

In the border state of Texas, Land Commissioner Dawn Buckingham offered the administration a tract of more than 1,400 acres to stage its mass deportation operation.

Her letter to Trump, obtained by Fox News Digital, says her office is “fully prepared to enter into an agreement with the Department of Homeland Security, Immigration and Customs Enforcement, or the United States Border Patrol to allow a facility to be built for the processing, detention, and coordination of the largest deportation of violent criminals in the nation’s history.”

Fox News Digital has reached out to the mayor’s offices in Boston, Los Angeles, San Diego, San Francisco, Chicago and Denver.

Fox News’ Michael Dorgan and Adam Shaw contributed to this report.