NewsNation) — Patrolling more than 1,900 miles of the U.S.-Mexico border falls under federal jurisdiction, but if President-elect Donald Trump bulks up manpower to go after immigrants who entered the country illegally as he has pledged, local law enforcement agencies could also be called into action. 

Trump has doubled down on plans for the largest domestic deportation in American history, focusing initially on immigrants who have been convicted of serious crimes. 

As Trump’s inauguration draws closer, agencies on the front lines of border crimes and the entry of millions of immigrants expect a noticeable shift. 

Republican Sheriff Mark Dannels in Arizona’s Cochise County says intensified federal attention to the border crisis will provide relief to his 100 deputized officers who patrol 6,200 square miles of rural desert that runs 83 miles along the U.S.-Mexico border. 

Cochise deputies have made 4,000 arrests in the past 35 months involving border crimes including human and drug smuggling. 

Dannels says officers are stressed and have risked serious injury and death in apprehending offenders. The incoming administration has created optimism, the sheriff said. 

“You’ve got a president who has already made it very clear …and comes with a report card of border security being a priority – that he’s going to come in and do the federal government’s job. And that is, do what you’re supposed to do,” Dannels told NewsNation. 

Border sheriffs expect help from Trump administration 

Cochise County already partners with 100 federal and state agents and officers at a unique operations station to patrol 83 miles of the border.

Border crossings aren’t the main issue for Cochise County deputies, as many of the migrants that come through the county head to urban areas.  

Instead, deputies are tasked with tackling crime at the border, such as drug smuggling.  

In almost three years, the department has arrested 4,000 people for border-related crimes, Dannels said most of them are Americans working with the cartels.  

Receiving more White House support will allow deputies to get back to “doing what they do best,” Dannels said.  

“We’ve covered the bill,” Dannels said. “It’s time for them to reimburse us and cover their own debt and do their job.” 

Some agencies speculate that removing an estimated 11 million immigrants could cost the federal government nearly $970 billion over 10 years. 

Texas is prepared to offer up 1,400 acres of land to build a detention facility to aid Trump with his mass deportation efforts, according to a letter obtained by NewsNation. Texas Land Commissioner Dawn Buckingham sent the letter to Trump offering the land, which is located in the Rio Grande Valley sector near the U.S. Mexican border. 

Buckingham told Trump that her office is prepared to cooperate with ICE, the Department of Homeland Security and the U.S. Border Patrol for the facility. 

Thaddeus Cleveland, a retired Border Patrol agent and the Terrell County Texas sheriff since 2022, oversees a department that covers 2,300 square miles, including a 54-mile stretch along the border.   

He told NewsNation he’s ready for backup considering the fact his small department covers 2,300 square miles of territory and 54 miles along the border. 

Terrell County experienced a 417% jump in border apprehensions in fiscal year 2022, Cleveland said. The department already has existing relationships with U.S. Customs and Border Protection and the Texas Department of Public Safety.  

Cleveland knows that under Trump’s leadership, his department will benefit from increased support — even if it is asked to assist federal agents with locating and apprehension of illegal immigrants as is authorized under ICE’s 287 (g) Immigration and Nationality Act. 

“We’re not afraid to be in the fight,” Cleveland said. 

Joe Frank Martinez was recently elected for his fifth term as sheriff in Val Verde, Texas, which shares 150 border miles with Mexico along the Rio Grande River. His department includes four deputies to police the 3,200 square miles that make up the county. 

In 2021, roughly 3,000 mostly Haitian immigrants congregated under an international bridge for two weeks, creating an emergency in Del Rio and for Martinez’s small department. Although Val Verde County has seen immigrant encounters diminish since 2023, Martinez acknowledges more needs to be done. 

That’s especially true in a rural area of Texas where protective structures – like Trump’s unfinished border wall – have fallen into disrepair and include gaps. Martinez, a Democrat, says even though significant border encounters aren’t particularly problematic for his department these days, it doesn’t mean that’s the case everywhere. 

“This shouldn’t be a red or blue issue,” Martinez said. “I think that both sides need to come together and come up with a solution. If (a border wall) is the solution that is going to keep our community safe, I’m for it.” 

Where state laws prohibit local enforcement of immigration  

In California, which has been among the states affected most by illegal border crossings, local law enforcement officials are limited in their ability to make arrests of those entering the state. 

The CBP San Diego sector reported more than 9,500 migrant arrests in a single week in April of this year. It marked the first time since 1999 that the sector tallied the most arrests of any region, the Los Angeles Times reported.  

That number grew to 14,436 in August, according to CBP data cited by the Washington Office on Latin America. Despite the number of arrests made along the border by federal agents, California state law defines the role of agencies including the San Diego Sheriff’s Department. 

A department spokesman told NewsNation that local deputies are regularly used to assist immigrants who have already crossed the border and need humanitarian aid. However, the department’s involvement stops there, leaving any immigration enforecement work to the feds. 

The spokesman said any change in department policy would require a change to state law. Should that happen, the spokesman said the department would review the amendments and its current policies before considering any changes. The spokesman declined to speculate what could happen under Trump. 

“We support the efforts of the United States Border Patrol, who have an extremely challenging and dangerous job,” the spokesman said. 

NewsNation’s Ali Bradley contributed reporting to this report