Along the border, Guatemalans poach game and plants from Belize's national parks.

ECONOMIST: Immigrants in Belize

One trick is to build plants just over the border in a more welcoming country: Sempra, an American firm, has built a regasification plant in Mexico, just across the border from California, where regulators have yet to approve such a facility.

ECONOMIST: Liquefied natural gas

To the south, in Juarez, there are new highways and overpasses connecting the manufacturing plants to the cross-border transit routes.

FORBES: Why Is Mexico's Murder City Attracting Investors?

The United States, for example, has long granted preferential access to goods assembled in Mexican maquiladora plants using components from north of the border.

ECONOMIST: Do regional trade agreements encourage free trade?

Meanwhile Clean Energy has teamed up with truck stop operator Pilot-Flying J to build a border-to-border network (to include these GE Micro LNG plants) by the end of 2013.

FORBES: Acceleration of the Natural Gas Highway

Many of the companies represented in her delegation have plants and factories in the frontier provinces on the Afghan border, a part of the country that might spook American investors.

FORBES: Ambassador To Pakistan's Economy

Every large border town has, loitering round the bus stations, recruiters for slaughterhouses or chicken-processing plants across the mid-west.

ECONOMIST: The keenest recruits to the dream

Outside of oil and gas, Hunt owns stakes in power plants in the Northeast, transmission lines in Texas, including a 150 megawatt cross-border line with Mexico built in 2007.

FORBES: 'Dallas' Actor Hawks Solar Power, But Billionaire Who Inspired J.R. Ewing Is Focused On Natural Gas