Idaho has vast stretches of desert, topographically speaking.

But a pro-school choice think tank mapped out a different patch of “charter school desert” — a pocket of the Treasure Valley northwest of Boise.

It’s an area with high poverty and a shortage of charter schools, the Thomas B. Fordham Institute said in a report issued Thursday.

“Many families lack the financial means to move out of neighborhoods when dissatisfied with their schooling options, so the location of schools is key to ensuring access and equity for all students,” the report says.

The institute’s “desert” definition doesn’t include every area without a charter school, which may explain why the report says nothing about rural Idaho. Rather, the definition focuses on potential market share: areas with large concentrations of students in poverty.

Consequently, the report concludes that the charter sector needs to think beyond inner cities, and open schools in suburbs and rural areas. And charter advocates need to examine the “policy and practical barriers” that keep charter schools from locating where they’re needed.

But relatively speaking, that is not much of a problem in Idaho. Of the 42 states with charter schools, 20 have 10 or more charter school “deserts,” according to the Fordham Institute report. Alaska, Idaho and Wyoming have only one charter “desert.” Hawaii, Iowa and New Hampshire have no “deserts.”

Click here to download the report.