Jeremiah Heaton’s 7-year-old daughter Emily wanted to be a princess. Not wanting to disappoint her, Mr. Heaton traveled from Abingdon, Virginia, early last summer to an area of unclaimed land in Africa, planted a flag and declared it the “Kingdom of North Sudan.” Mr. Heaton is the would-be king; his daughter by rights would become a princess.

As crazy as this story sounds, some international lawyers say Mr. Heaton has the beginnings of a legitimate claim to the land. If he does achieve recognition, which is problematic, he could set an example for the rest of Africa by turning the patch of desert into a sanctuary for economic freedom.

The area claimed by Mr. Heaton is called Bir Tawil, 800 square miles of unpopulated land along the southern border of Egypt and the northern border of Sudan. Since 1902, neither country has claimed Bir Tawil because doing so would mean giving up claims to a larger adjoining region called the Hala’ib Triangle, valued more highly for its agriculture and access to the Red Sea. As a result, Bir Tawil has remained “terra nullius,” or no-man’s land, for more than 100 years.

To be considered a sovereign nation under international law the “kingdom” would need a permanent population occupying the land for several years, a defined territory, a government, and the capacity to enter into relations with other states.

Mr. Heaton has a lot of work to do, having no more at this stage, perhaps, than a defined territory. But he’s determined. His current focus: receiving recognition from Egypt, Sudan and the African Union.

Let’s dream big like Emily and imagine Mr. Heaton achieves his goal. What next?

First, Mr. Heaton should do something that’s unusual in that part of the world: establish a country that abides by the rule of law, and protects private property rights and the freedom to trade. If he were to do this, and if he could secure the area from outside incursions, he could create an economic sanctuary that would rival any in the world.

Hong Kong was once a cluster of rocks half the size of Bir Tawil. Dubai was once a sandy desert. Today they are leading centers of international finance and commerce and two of the wealthiest places on earth. Dubai has the fifth-fastest growing economy in the world thanks to its many “free zones” that place virtually no taxes or restrictions on foreign trade.

Both Hong Kong, which was ruled by Britain for 156 years, and Dubai embrace English common law and global trade. This has attracted private capital and entrepreneurs, lifting countless others out of crushing poverty. Africa needs this more than anywhere with nearly half its population living on less than $1.25 per day.

Disease is rampant in Africa with Ebola, malaria, yellow fever, whooping cough, tuberculosis and measles killing millions each year. Nearly 40 percent of African adults are illiterate, two-thirds of them women. The continent needs hope and deserves a better future.

One online cynic wrote: “I’m guessing the funds required for Heaton’s Bir Tawil odyssey could have financed a generous charitable donation to help a struggling region.” But this approach to African development has been tried and largely failed. Rather than handouts, Africa needs capital investment, entrepreneurial innovation and free trade. Mr. Heaton understands this.

Since he planted the flag in June 2014, Mr. Heaton’s plans for development have started to take shape. He wants to transform Bir Tawil into a “test bed” for scientific research on food security, renewable energy, digital commerce and digital currencies, and thereby establish a permanent population.

The journey that started with a little girl’s dream is still that, but dreams can be seedbeds of massive change. Mr. Heaton’s vision, according to news reports, already has sparked interest among entrepreneurs from Australia, Germany and India. Crowdfunding could launch some of the projects. It also has sparked interest in Hollywood with a possible movie to be called “The Princess of North Sudan.”

Dreams that spark real economic change in Africa are something the continent desperately needs. Mr. Heaton’s goal is a long shot, but stranger things have happened. And this dream, were it to become reality, could lift millions out of poverty and into self-sustaining prosperity.