Simply because of Trump's rhetoric by his 100th day in office, borders crossings were reported to have fallen by 73%.

President Trump secured $1.6 billion for border wall construction in the March 2018 omnibus bill.

February 15, 2019. Trump declared a national emergency to allocate funds to build a wall on the border with Mexico. During the announcement, the president says he expects the declaration to be challenged in court, which it was. According to the White House, up to $8.1 billion will become available to build the border wall including: $601 million from the Treasury Forfeiture Fund, up to $2.5 billion under the Department of Defense funds transferred for Support for Counter-drug Activities, up to $3.6 billion reallocation from the Department of Defense military construction projects, and the $1.375 billion from a congressional spending package.

Since Trump took office not a single cage has been constructed to hold migrants. All those cages seen on the news were constructed by President Obama's administration and previous administrations. "I've been to that facility, where they talk about cages. That facility was built under President Obama under (Homeland Security) Secretary Jeh Johnson. I was there when it was built," said Thomas Homan, who was Obama's executive associate director of Immigration and Customs Enforcement for nearly four years.

May 30, 2019. Trump threatened to impose new tariffs on Mexico if the country did not step up its immigration enforcement actions, saying in a White House statement that a round of tariffs would begin on June 10 at 5% "on all goods imported from Mexico." The statement warned further that if Mexico does not act as Trump's demands, tariffs would continue to increase up to a permanent level of 25% by October. June 7, 2019, Trump says tariffs on Mexican goods are "indefinitely suspended" after negotiators from the US and Mexico were able to reach a deal on immigration enforcement. According to the Washington Post, the number of family-unit apprehensions on the southern border has declined about 13 percent since the start of June that year. The decline is partly attributed to action taken by Mexico to more strictly enforce its border to avoid the possible imposition of tariffs.

President Trump labeled Democrats "border deniers" for their pro-open borders policies.

Trump gave the Democrats the option of allowing illegal immigrants into sanctuary cities in exchange for funding for the Border Wall, and they refused.

In August 2019 border patrol unveiled 60 new miles of border wall built in Arizona and expected another 450 miles to be built by the end of 2020.

Illegal immigration declined dramatically after Trump took office. According to data released early in Trump's presidency, illegal border crossings decreased by 40% in the first month a remarkable achievement, considering that illegal immigration usually increases by 10 to 20% in January and February.

Under Trump, Customs and Border Protection apprehended 17,256 criminals and 1,019 gang members in 2018. ICE's Enforcement and Removal Operations arrested 158,581 aliens in 2018, an 11 percent increase from 2017. Ninety percent of those arrested had criminal convictions, pending charges, or had been issued final orders of removal. CE ERO increased removals by 13 percent in 2018 to 256,086, the majority of whom were convicted criminals. Removals of convicted criminal aliens increased by 14 percent from 2017. Nearly 6,000 known or suspected gang members were removed in 2018, a 9 percent increase from 2017. The Department of Justice prosecuted a record number of criminal immigration offenses in 2018 and increased the number of prosecutions for illegal entry by 84 percent over 2017.

Trump getting Mexico to aid in stopping illegals from entering the United States is credited in helping reduce the number of people apprehended by 22% in 2019.Trump reaffirms that the numbers are still at a crisis level and more work is needed to be done.

Trump has convinced the Salvadoran government to deploy hundreds of police, soldiers, and agents totaling over a thousand to its border with Guatemala to aid in preventing future illegal aliens from making it to the US. Because of Trump's policies the DHS's Office of Immigration Statistics, illegally entering the U.S. from Mexico was harder than it had ever been in decades, at least, and smuggling costs doubled from the late 2000s.

H.R. 244, which was signed into law by President Trump on May 5, 2017, and funded the government through September 30, 2017, did not include funding for several of President Trump's priorities, such as defunding sanctuary cities and building new sections of the border wall. However, it did include an additional $1.5 billion in border security funding, including money to repair 40 miles of existing border barrier sections and to increase funding for ICE and CBP, among other conservative achievements.

July 17, 2017. The Trump Administration, in a break with the Obama Administration's refusal to do likewise, gave $2.3 million to the state of Texas so its military patrol could continue patrolling the border with Mexico.

March 23, 2018. Despite doing significantly less to advance his conservative immigration agenda than he hoped, the omnibus bill that President Trump signed did spend nearly $1.6 billion on border security, including money for building new sections of the border barrier, repairing existing sections, and building secondary fencing.

April 4, 2018. President Trump signed an order deploying National Guard soldiers to secure the border and assist border patrol agents. The Department of Defense quickly took steps to deploy National Guard troops, and Secretary of Defense James Mattis signed an order on April 6, 2018, to approve funding for up to 4,000 troops. By May 9, 2018, the CBP announced that because of the National Guard troops it had apprehended 1 ,600 additional illegals and turned back an additional 451.

October 26, 2018. Directed by Trump, Defense Secretary Mattis approved a request from the DHS to send an unspecified number of active-duty soldiers to the border with Mexico to help U.S. Border Patrol, something done as a large migrant caravan approached the U.S. On October 29, 2018, the Pentagon announced it would initially deploy about 5,200 troops to the border, and U.S. troops began deployment shortly afterward. The soldiers immediately went to work securing the border and put up several miles of razor wire on existing border barriers. On December 4, 2018, Defense Secretary Mattis approved a DHS request to extend troop employment until January 31 , 2019, from the original end date of December 15, 2018.

Among other border security improvements, the Trump administration constructed 20 miles of new and improved fencing in New Mexico. The DHS also constructed 2.25 miles of improved fencing and border infrastructure at Calexico, California, as well as 14 miles in San Diego. The Rio Grande Valley also saw improved border security measures, and the DHS waived environmental regulations in 2018 to expedite the construction of about 17 miles of wall in the area. In September 2018, the CBP began construction of an improved four-mile border barrier in El Paso. The CBP also began preparations for a six-mile border wall construction project in Texas scheduled to begin in February 2019, an eight-mile construction project in Texas scheduled to begin at the same time, and a 32- mile wall replacement project in Arizona to start in April 2019. February 2019, the DHS waived several environmental laws to allow it to build several miles of wall in San Diego, and construction began later that month. In April 2019, the CBP began construction of 13 miles of wall in Texas. On April 27, 2019, the DHS waived environmental laws to speed up the building of 53 miles of wall in Arizona and Texas, and on May 14, 2019, it again waived environmental laws to speed up border wall construction in California and Arizona. In May 2019, Customs and Border Protection approved a $42.8 million contract to build three miles of border wall in Starr County, Texas. On June 27, 2019, the federal government announced a contract to build four miles of border wall in Texas.

July 1, 2019. President Trump signed a $4.6 billion humanitarian border spending bill. Democrat House Speaker Nancy Pelosi failed to pass a partisan left-wing bill and caved into passing a bipartisan Senate bill, though the Senate bill also included some liberal provisions.

March 15, 2019. President Trump signed an executive order that updated a 2011 order signed by President Obama, strengthening the definition of a "significant transnational criminal organization" so that the Trump Administration could better counter Mexican cartels and other similar organizations.

May 8, 2019. The Trump administration moved to implement a program to allow Border Patrol agents to act as asylum officers to help reduce mass migration and speech up asylum claim processing.

In a Trump victory, the Supreme Court ruled in his favor when they struck down a block which will now allow Trump to appropriate military funding to build the border wall.