The Trump administration faces new legal challenges over the national emergency declaration to pay for a wall on the U.S.-Mexico border after the American Civil Liberties Union filed a lawsuit Tuesday. A group of 16 states filed a separate suit Monday that called the emergency declaration unconstitutional.

Several landowners on the border are also fighting back. Some landowners in the Mission, Texas, area have received notices of surveys and even some letters to buy their property. But now, some are suing the government to keep what they say is rightfully theirs.

A small, 1-acre piece of land along the Rio Grande River was left to Yvette Gaytan by her father. The land that's been in her family for about six to seven generations is now at risk of being taken away by the government for a new border wall, so she's suing the Trump administration to keep it.

"I'm fighting his idea of what he thinks we need," Gaytan said. "They're going to take what I have left of my parents."

Last week the Department of Defense released a statement saying the national emergency declaration "authorizes the secretary of defense to determine whether border barriers are necessary."

Marianna Trevino Wright is the executive director of the National Butterfly Center, a facility that could lose about 70 acres of land.

"I hope it's a wake up call for all Americans that this administration that purports to be all about law and order is, in fact, lawless," Trevino Wright said.

We visited land right near the National Butterfly Center. It's a national preserve that belongs to the federal government. Signs went up last week warning people that they cannot go beyond this yellow line. It's restricted because, inevitably, it's where new portions of the border wall will be built.

A lawsuit filed by the Butterfly Center in 2017 to stop the wall was dismissed last week. 

"Is there a fear that this might be what's in store for other landowners?" Villarreal asked.

"I think it's a very real possibility and they should be prepared for the worst," Trevino Wright said.

Gaytan said she's willing to fight for it still "because it means everything to me."

"It means everything to me, to my kids. My sons saw my dad as more of a father than a grandfather, and to know that they're going to lose the last bit that we have of him is not easy," Gaytan said. 

Just over here is the historic La Lomita Chapel. For now it has been spared, but with the proposal for the wall still underway, they say they are not out of the woods just yet. The White House and the Department of Homeland Security refused to comment about these lawsuits.