Many cities experienced an urban renaissance as millennials came of age in the 2000s and early 2010s and reshaped neighborhoods in what came to be known as the ‘back to the city’ movement. As millennials aged, however, their residential mobility patterns shifted. Increasingly, they moved out of cities and into suburban areas. In a new paper co-authored with Hyojung Lee, we found that this suburbanization may have been motivated by the lack of affordable and right-sized housing in urban areas, factors that outweighed proximity to desirable amenities. Our findings have implications for planners in both urban and suburban communities as they hope to attract and retain the nation’s largest generation.

While generations are subjective concepts and there are different approaches for defining them, we considered someone to be a millennial if they were born between 1977 and 1996. Within that, we split the cohort into ‘early’ (born 1977–1986) and ‘late’ millennials (born 1987–1996). Our paper focused on early millennials in particular, as they were old enough to make independent mobility decisions in 2011 (aged 25–34) and in 2021 (aged 35–44). We analyzed this cohort’s mobility patterns using American Community Survey 5-year estimates from 2007–2011 and 2017–2021 to cover both the post-recessionary period and the pandemic—though given the range of years, we were not able to parse pandemic-era changes from the preceding years.

Using these data, we found that throughout the past decade millennials were moving to suburbs that were farther out from the city center. There are many ways to define suburbs, and in this paper we rely on a framework that considers rates of homeownership, single-family housing, and car commuting, in addition to proximity to a metro’s urban core. While there is extensive research and discussion about millennial preferences for walkable urban areas, we found that the places with the largest increases of early millennials were both suburban and on the periphery of metropolitan areas.

And while millennials potentially have a preference for amenity-rich neighborhoods, they were typically leaving these neighborhoods for those with fewer amenities. Amenities often change, however, and we observed a notable increase in the number of amenities in the peripheral suburban areas that gained the most millennials between 2011 and 2021. We could not tell from the data whether the presence of millennials motivated the increase in amenities or whether the amenities drew in more millennials—or both—but these neighborhoods certainly began offering more during this period of suburbanization.

So why would millennials abandon their urban preference for places that were more suburban, less central, and lighter on amenities? We found evidence that affordability and the changing housing needs of millennials may be important drivers. Millennial suburbanization was strongest in metros with the least affordable urban centers and in those with the lowest shares of family-sized housing units (those with three or more bedrooms) in their urban centers. This suggests that millennials are leaving places that do not offer affordable and/or right-sized housing as they reach traditional milestones like forming a new household, having children, or becoming homeowners.

Despite increasing suburbanization, millennials continue to occupy urban areas in high numbers. Late millennials were still moving into central and peripheral urban areas in 2021, and even early millennials lived in urban areas at higher rates than Gen X and baby boomers did at that age. Neither are cities completely out of luck, as Gen Z is now driving new rental demand and moving into urban areas, in line with the hypothesis that urban areas are ‘youthified’ in how they are shaped to meet demands of young adults through small housing units and amenities. It may be because of this youthification, however, that cities are poorly situated to retain millennials as they age.

It may be the case that millennials prefer urban living, despite their recent suburbanization. We do not have good data on the reasons they have moved to the periphery. Indeed, the growth of amenities in the peripheral suburban areas where millennials moved offers some evidence that their urban preferences may yet be alive and well. This suburbanization may instead be a direct result of the ongoing lack of affordable, diverse housing types in central urban areas. Planners and policymakers in both urban and suburban areas who hope to attract and retain millennials as well as future generations will need to provide affordable, right-sized housing options and amenities that appeal to an array of age groups.