Des Moines doesn't have a reputation for being particularly hip … or space-constrained. In this city of a bit more than 200,000 people, you can buy a three-bedroom house for less than $150,000 and find yourself a short drive from acres of rolling farmland. The local culture blog is called Des Moines Is Not Boring—a pretty good indication that it very well might be.

That makes the city a surprising place to find a growing market for micro-apartments—an imprecise term describing units that are smaller than traditional studios. The emergence of micro-apartments, a phenomenon more often associated with big, expensive cities, such as New York or San Francisco, signals an effort to attract young renters who are inclined to make the city their living room, as the pitch goes, and sleep on beds that fold into walls.

And yet here they are in Des Moines—in a converted, century-old office building, and in a new development with such luxury amenities as a yoga studio and cinema room. Renters can expect to pay about $850 for about 450 square feet—assuming there's a vacancy. Rick Tollakson, chief executive of Hubbell Apartment Living, says that the micro units in his company's Cityville on 9th development are fully leased. "Like any other city, there's a demand for downtown living," he says. "And if you want to want to lease an apartment for under $1,000 and live by yourself, it pretty much has to be a micro."

Indeed, the micro-apartments cropping up in Des Moines and other less-likely metros, including Columbus and Omaha, also signal two overlooked conditions. Interest in downtown living has extended beyond coastal cities known for vertiginous housing prices. And the rental crunch that has long led residents in crowded coastal cities to pay high prices for tiny abodes is surprisingly widespread. Nationwide, more than two of five renters spend 35 percent of their income or more on housing, according to the Urban Institute, and the rental affordability crisis has landed in boom towns such as San Jose as well as such busts as Detroit. 

In that light, the shift toward smaller apartments can be seen as simple economics: Smaller apartments are more profitable for developers to build and more affordable for tenants to rent. "I could paint a cooler picture about value of design, efficiency, and all of that," says Alexander Grgurich, a development analyst at Nelson Construction & Development, which converted a century-old office building in Des Moines into 425-square-foot apartments in 2013. "For us, it's about getting a higher price per square foot while offering a lower absolute rent to the renter."