In the midst U.S. economic expansion that’s breaking records for its longevity, the under-recognized growth stars of America are its small and medium-size towns and cities.

Many such U.S. towns have impressive growth stories—and there is strong future economic potential in places often overlooked by construction firms and developers, realtors and others with a strong business interest in where America is booming.

A large share of America’s economy is clustered in its 10 largest cities, accounting for a third of U.S. economic output, despite only 26% of Americans calling these cities home. But what is less recognized is that around two-thirds of its economic output is generated by medium- and small-size towns and cities. In a large number of these smaller metros, the underlying industrial base and demographics are upbeat.

Drawing on its unique online databank of key indicators for more than 3,500 U.S. city and regional economies, Oxford Economics, the global advisory firm, has analyzed growth prospects and key trends for 382 individual metro areas and 3,142 counties across America to map their fortunes.

The analysis reveals that of the top 20 metros for forecast economic growth through 2022, nine have fewer than 500,000 residents. Many of these small- and medium-size growth stars among U.S. towns and cities, such as Midland and Odessa in Texas, are in the Southwest and Mountains region, and are benefiting from a buoyant energy sector, sturdy in-migration and an evolving economic base.

Unlike larger metros, smaller places typically rely on a single industry to support employment, consumption and investment—and if that base industry is seeing sturdy growth, so will that city.

Another important driving force in fast-growing smaller urban centers is in-migration, which can be seen in towns such as Provo and St. George, Utah, as well as Boise, Idaho, where a mix of retirees and young families escaping high living costs on the Pacific coast is supporting population-driven industries (such as construction, health care and real estate). Boise also has exposure to semi-conductor production, one of the country’s fastest-growing industries. There is even robust growth among small Midwestern manufacturing hubs, with growth in recreational vehicle manufacturing putting Elkhart, Indiana, on the map, for example.

It is important, though, to recognize that alongside such strong growth stories in America’s smaller towns and cities, other metros have a less rosy tale to tell. Oxford Economics’ analysis shows that 72% of all U.S. metros will lag average US economic growth over the next five years.

Metros in the Midwest and East will continue to lag in general. More than 80% of Midwestern metros are set to underperform average U.S. growth, with many of these places, large and small, feeling the economic drag from automation, globalization and de-industrialization.

Places with the best employment and demographic growth rates tend to cluster, meanwhile. Regions of note include Colorado’s Front Range and the I-85 Corridor that links growing communities from Atlanta to Raleigh.

In the mature stages of a very long economic cycle, and with the national labor market tight given a 3.7% unemployment rate, the varied economic geography of America’s metros is also reflected in employment trends.

The lowest unemployment is generally found in larger metros and especially those that are digitally adept. Not surprisingly, jobs markets that have performed best are in a few key clusters, such as coastal California, the Pacific Northwest and the Boston-Washington corridor. But future hiring in these coastal hubs is likely to be muted since their labor markets are already so tight, and labor force growth is expected to be tepid at best.

Oxford Economics’ analysis sees particularly high employment levels in certain smaller metro clusters, especially those lucky enough to have the right industry mix—or geology, in the case of western Texas and North Dakota.

Sustained in-migration to communities such as Longmont, Fort Collins and Colorado Springs, Colorado, is generating notable growth in population-driven industries. But more importantly, the Front Range’s economy continues to evolve towards productive industries that support higher-paying occupations.

Sturdy population growth plays an important role in job growth in many small metros. Aside from providing labor market capacity, newcomers demand services that drive further employment. This is especially evident in Florida, where many retirees are moving to small communities such as Sarasota and The Villages.

Outside of Florida, however, the parts of the American South that are creating jobs and pulling in more residents are typically those with the best industry mix. Consider the cluster of cities along the Interstate-85 corridor, which links service-based economies such as Atlanta, Charlotte and Raleigh with modern, globally-integrated manufacturing hubs such as Greenville and Spartanburg, South Carolina.

Oxford Economics’ greatly expanded U.S. cities and regions forecasting service offers an unprecedented capability to forecast and analyze more than 3,500 sub-national economies across America. The online databank provides historical data and forecasts across U.S. locations to 2035 and covers a wide range of indicators including GDP and employment by sector, household incomes, wages and spending, demographics and housing forecasts.