"Some of them, you want to cry when you see them. Others, you want to cut their throats," Cunningham says.
In the past few years, they've been crossing by the hundreds every day, keeping border patrol agents so busy they had little time to chase the drug runners who worked this territory as well. It was so bad, Cunningham wouldn't show his face when he spoke with CBS News seven years ago. Times have changed.
"Definitely seen a dramatic improvement. The numbers have decreased so much," Cunningham says today.
That's because the days of being captured — then released — are over. Now, every man or woman caught crossing the border illegally here is prosecuted and put behind bars.
Instead of an overnight stay in a detention center, illegal immigrants have spent anywhere from two weeks to six months in jail. Then they're sent back to their home country.
Maria Tovar came looking for work as a maid. She says she won't try to cross here again because she was treated like a criminal.
The word seems to be out. These days, this stretch of the Rio Grande is quiet.
In Eagle Pass, apprehensions have dropped 71 percent in one year, and with agents spending less time chasing people, drug seizures have jumped more than 300 percent.
"We have gotten to the point where we have a very safe, controlled border out here that we didn't have in the past," Border Patrol agent Randy Clark says.
The strategy could be a model for other parts of the border. It works along this stretch because they have jail space and judges who can handle the workload. Even so, Dub Cunningham worries illegal immigrants will eventually find another way in.
"You got to understand that we're sitting next to a country that's over-populated, under-employed with a corrupt government and you can't blame one of them for leaving that situation," he says.
Still, he's thankful for the peace this program has brought to his land.