SAN DIEGO -- For Bob Maupin, it is a gargantuan attempt to protect and secure his 250-acre ranch.

His property sits just yards from the U.S.-Mexico border.

“They want to jump across this road so they won't be seen and get past this fence,” said Maupin.

He said he has spent the last 15 years slowly building a chain-link fence that is 10 feet high and 2,000 yards long.

Maupin’s mission is to stop what has been a rush of illegal crossings into the U.S. through his land.

“People cross every single night and more than one group,” said Maupin.

Regarding the fence, Maupin said it works.

Night vision video taken on Maupin’s land last month showed what turned out to be five illegal immigrants attempting to cross. However, the group was turned back when they could not get through the fence.

Not every illegal crossing can be stopped, with 66 miles of international border in the San Diego sector alone.

The U.S. Office of Immigration estimated that 2.8 million illegal immigrants are currently in California.

Those numbers forced the deployment of the National Guard to the U.S.-Mexico border last spring to help with border security.

While he said the number of illegal crossings are down, the commissioner for the U.S. Customs and Border Protection said last week that the job is far from over.

“Are we at a point yet where we can put our flag in the ground and declare victory? No, I would say not,” said W. Ralph Basham.

A volunteer group called the Minutemen has come up with their own solution, patrolling the borders on their own.

Some of the Minutemen have changed their strategy. They are pulling back from the U.S.-Mexico border and are now trying to break up day labor gatherings across the country, warning potential employers about the crime of hiring illegal immigrants.

“We have to secure the border and then stop the magnet that brings them here, which is the plentiful jobs. There is no shortage of people that will hire them for cheap labor,” said Jeff Schwilk of the San Diego Minutemen.

The problem is not just with day laborers or even drug traffickers.

The threat of terrorism is now another concern with border security.

The U.S. border could be a possible entry way for terrorists and San Diego, with its massive military presence, could make for a tempting target.

“We have a tremendous amount of military bases and power here and this would probably be a very good target,” said retired Vice Admiral Edward H. Martin.

Maupin said he is troubled because he has seen people from as far away as China and the Middle East trying to cross into the U.S. through his land.