Texas has the longest border with Mexico of any U.S. state, sharing 1,254 miles with its southern neighbor – making it ground zero in the international fight over undocumented immigration.

The numbers of immigrants crossing the border that stretches from Brownsville to El Paso has dipped in recent months but broke records in 2023. The Republican-dominated state waged its own war — overseen by Gov. Greg Abbott — on illegal immigration and in opposition to the Democrat-backed policies of President Joe Biden.

Now, Abbott will announce a new border strategy at an event in Eagle Pass on Thursday.

Here are five key things to know about immigration in the state:

Texas spends billions on border security

Texas has funneled dollars into its own border security initiatives for nearly 20 years, starting with Operation Linebacker in 2005, Operation Rio Grande in 2006, and Operation Wrangler in 2007 – all funded with tens of millions in federal grants awarded through then-Gov. Rick Perry’s office.

In 2007, lawmakers allocated $110 million in state tax dollars to create Operation Border Star, which uses information sharing between federal, state and local law enforcement to bolster efforts along the border. By 2013, Texas had spent nearly half a billion in taxpayer money to supplement federal border programs.

Over the next decade, as Republicans tightened their grip on state leadership and undocumented immigration launched into the political spotlight, funding for border projects soared.

State lawmakers in 2023 allocated $4.6 billion for border security programs in local communities and across Texas.

Operation Lone Star has cost taxpayers $11 billion

Abbott launched Operation Lone Star in March 2021, deploying National Guard soldiers and state troopers to the border with Mexico to deter undocumented immigration.

The initiative included erecting barriers, stationing law enforcement along the border, busing migrants to other states and creating migrant-processing centers.

Operation Lone Star encompasses many of the aspects of its early predecessors and now serves as an umbrella strategy for efforts across several state agencies. Abbott now wants $2.9 billion to keep the program going through at least 2027.

Texas wants its money back from the feds

A proposal filed earlier this year by U.S. Rep. Roger Williams, R-Willow Park, would require the federal government to reimburse the state for its losses and expenses incurred during any border operations since 2020.

The federal government bears the responsibility of enforcing its international borders, mainly through the U.S. Department of Homeland Security and U.S. Department of Justice. The U.S. constitution authorizes the government to require citizenship to participate in its systems of democracy, which makes the feds the primary stewards of immigration into the country.

Williams and other state leaders argue, then, that the federal government owes Texas because it has failed to secure the Texas-Mexico border and cost state taxpayers money. Reimbursement should include expenses incurred by Operation Lone Star as well as potentially billions allocated to agencies such as the Texas Department of Public Safety and the Texas National Guard, according to the congressman’s proposal.

Texas is buying border land, bracing for proposed mass deportations

In November, officials unveiled a ranch in Rio Grande City that the state purchased on the Texas-Mexico border.

Texas officials offered it as a site for detention facilities to help the incoming administration of President-elect Donald Trump with proposed mass deportations. Portions of a border wall have already been built at the site.

Meanwhile, Texas Land Commissioner Dawn Buckingham has said the state is searching for additional land to aid the federal effort.

Texas Attorney General Ken Paxton sued the Biden Administration over immigration

Paxton has gone to court to protect Abbott’s efforts to build a border wall and install buoys and razor wire in the Rio Grande River.

He challenged policies that conservatives say contribute to illegal immigration. He has successfully used the courts to halt immigration policies that included the Deferred Action for Childhood Arrivals, which allowed some undocumented immigrants who got to the U.S. while younger than 16 to work in the country, delaying deportation.