Nanopolitans and Picopolitans: Exploring the Value of Core-Based Definitions Below the Micropolitan Level

Federal definitions of core-based metropolitan and micropolitan statistical areas (CBSAs) recognize the importance of large, central places in broader regional economies. Although CBSAs are officially defined for statistical reporting purposes only, the construct is widely used in regional science as a framework for analyzing economic change. Metro and micro area designations, by definition, exclude large swaths of territory often colloquially described as "rural." Half of all counties in Midwestern states and more than one third of all U.S. counties fall outside of a CBSA. While other county typologies exist to help characterize this remaining, undifferentiated space, few if any operationalize the importance of small central places as anchors for a broader region. This paper extends the concept of core-based areas definitions to include "nanoplitan" counties, which contain an urbanized area between 5,000 and 9,999 residents, and "picopolitan" counties, which contain an urbanized area between 2,500 and 4,999 residents. The paper examines whether these types of counties differ meaningfully in their economic structure and patterns of recent change. If so, an extended core-based typology may be useful for applied regional analysis and rural economic development outreach efforts.