On the campaign trail, Trump said he was going to create a "deportation force" and build a "beautiful" wall along the U.S.-Mexico border -- and get Mexico to pay for it.
In his first television interview as president-elect with CBS’ "60 Minutes," Trump said that once he takes office, he plans to immediately deport approximately 2 to 3 million undocumented immigrants.
Many of the cities that are pushing back have Democratic leadership and are already so-called "sanctuary cities," which generally means that they have in place some type of policy that discourages full cooperation with federal immigration authorities.
More people were deported under President Barack Obama than any previous administration, and for years, many local governments balked at the administration's deportation efforts.
In summer of 2015, Immigration and Customs Enforcement (ICE) implemented a new program to try to establish a better working relationship with local law enforcement. In cities that participate in the program, ICE will request to transfer certain convicted undocumented immigrants to federal custody, as well as ask for notification of release dates from local law enforcement custody.
Refusal to cooperate with federal law enforcement could jeopardize federal funding to state and local governments, something that Trump has threatened and will have the power to influence.
These are some of the major cities that are reasserting their immigration policies as the new administration is transitioning to power:
LAPD Chief Charlie Beck told the Los Angeles Times on Monday that regardless of Trump’s immigration push, the city will maintain its pro-immigrant policies.
"I don’t intend on doing anything different,” he told the newspaper. "We are not going to engage in law enforcement activities solely based on somebody’s immigration status. We are not going to work in conjunction with Homeland Security on deportation efforts. That is not our job, nor will I make it our job."
The city has pushed back against federal immigration authorities since 1979, when the LAPD began prohibiting officers from initiating police action with the objective of discovering the immigration status of a person.
New York City
Mayor Bill De Blasio met with Trump on Wednesday to share a number of concerns, including regaring Trump's proposed immigration policies.
The mayor said during a press briefing after he met with the president-elect that Trump’s proposed initiatives would create a rift between police and the communities they serve around the country.
He said that the proposals would “show distrust between law enforcement and neighborhoods would be counterproductive."
"I reiterated to him that this city and so many cities around the country will do all we can to protect our residents and to make sure families are not torn apart," said de Blasio.
He said in a tweet that he told Trump that New York City is the “ultimate city of immigrants” and that attempts to mass deport people “flies in the face of what makes NYC great.”
De Blasio also said that he would safeguard and maybe even destroy New York City identification card records, which contain information on undocumented immigrants, if necessary.
The City of Brotherly Love has been front-and-center in the battle between local government and federal immigration authorities.
As one of his first acts as mayor, Jim Kenney signed an executive order in January restoring the city's status as a sanctuary and barring most cooperation between police and ICE. The order states that city authorities will not cooperate with ICE detainer requests "for undocumented citizens who are arrested and would have otherwise been released from custody, unless the individual has committed a first- or second-degree felony involving violence."
On Monday, Mayor Kenney reaffirmed the city's stance on immigration in the wake of Trump's election, according to ABC affliate WPVI. "I vow to uphold the Fourth Amendment of the United States Constitution, yes, by not holding people in jail without a warrant, which I think is in violation of the U.S. Constitution," Kenney said.
The mayor’s office today issued guidance on "supporting diversity and inclusion," which included a list of resources for immigrants that are afraid of deportation.
Yesterday, Nashville Mayor Megan Barry issued a statement saying she does not believe that local resources should be used to enforce federal immigration policy.
"Our police officers are not immigration police, they do not ask about immigration status during stops or conversations with the public, nor do they intend to start now," she said.
She said she would do whatever she can to ensure that Nashville remains a "warm and welcoming city" for all.
On Monday, Mayor Rahm Emanuel, Obama’s former White House chief of staff, said that Chicago “always will be a sanctuary city.”
"You are safe in Chicago. You are secure in Chicago and you are supported in Chicago," Emanuel said, according to ABC-owned station WLS.
Mayor Ed Murray told a crowd Wednesday night that the city will remain a sanctuary for undocumented immigrants, reported The Seattle Times.
"These are our neighbors, and we will continue to support our neighbors,” Murray said. "We can’t allow ourselves to be divided and sorted out. That’s not America."
And on Tuesday, Police Chief Kathleen O’Toole confirmed that the policies of the Seattle Police Department regarding immigration status will not change.
"It is the intent of the Seattle Police Department to foster trust and cooperation with all people served by the Department," she wrote in a statement.
In a tweet, D.C. Mayor Muriel Bowser said the city will "remain a sanctuary city."