What is the smallest practical planning unit involved in regional planning?

In the context of regional planning, the county serves as the smallest practical planning unit because it encompasses a broader range of resources, communities, and administrative functions that need to be coordinated for effective planning. Counties typically manage various local governments and jurisdictions, providing a comprehensive framework for addressing regional issues such as transportation, infrastructure, land use, and environmental concerns.

By focusing on the county level, planners can better integrate services, policies, and land development strategies that impact multiple communities within its boundaries. This level allows for effective collaboration among smaller municipalities, making it easier to plan and implement regional initiatives that benefit the entire area. While cities, villages, and individuals are important units of analysis, they are often components of the larger systems that counties represent. Thus, the county captures the regional characteristics and challenges that need to be addressed holistically in planning efforts.