The first lady met with officials and employees at the facility, where 55 children aged 12 to 17 are housed.
The visit comes just hours after President Trump signed an executive order that barred "family separations" along the border; effectively allowing young children to remain with their parents while being processed by federal agents.
Melania said, "I want to thank you for your hard work, your compassion and your kindness you're giving them in these difficult times".
When Melania Trump met with detained children at the Texas border on Thursday, she struck a compassionate tone, asking staff at the facility: "How I can help. these children to reunite with their families as quickly as possible?"
Donald Trump is directing agencies to reunite immigrant families separated at the US-Mexico border, he said during a meeting with his cabinet at the White House.
"She wanted to see everything for herself".
Policy of separating children from parents is nothing short of torture
Trump's Republican party holds a majority in both houses of Congress but itself is divided on immigration policies. Some Republicans have split with the administration on the issue.
Brazil held to 1-1 draw by Switzerland in Group E opener
The nations are forever linked by Germany's 7-1 humiliation of host Brazil in the 2014 World Cup semifinals. But they couldn't get another one in front of a very Brazil-friendly crowd at the Rostov Arena.
Magnitude 6.1 quake kills three, stops factories in Japan's Osaka area
Osaka officials did not give details, but the injuries reported in Kyoto and three other neighboring prefectures were all minor. Minoru Yasui, an 80-year-old resident of Osaka's Higashiyodogawa Ward, was killed after a wall collapsed over him.
It is, however, unusual for Melania Trump to wear low-priced clothes when on public business.
The more conservative bill would deny the chance of future citizenship to "Dreamers" - immigrants brought illegally into the United States years ago when they were children.
Asked if they had any reaction to the charges against them being dropped, he said, "They're asking about their children, frankly". Plans for a visit to a second facility where children housed in cages were seen by The Associated Press last week were canceled because of flooding. "She thinks that it's important that children stay with their families", Grisham said. In a statement, the group's president, Steve Benjamin, mayor of Columbia, S.C., criticized Trump's "shameful policies" that have "traumatized thousands of lives". She spoke to many individually through a translator, and as she walked out she told them: "Be kind and nice to each other, OK?" There was a sharp increase in the amount of children taken away from their parents after Trump's administration started a "zero tolerance" policy that led to criminal charges against anyone caught illegally crossing the border.
"As with a many topics she will continue to give her husband her opinions", Grisham said.
"We have to have a very strong border", Trump said.
Hitting back, Melania's spokeswoman told her husband to "govern with heart". She had been expected to travel to promote the campaign but was sidelined a week after the announcement following surgery to treat a benign kidney condition.