Which term refers to the spread of a town or city into the surrounding countryside?

Urban sprawl is the term that best describes the spread of a town or city into the surrounding countryside. This phenomenon typically occurs when urban areas expand beyond their original boundaries, leading to the development of residential, commercial, and industrial spaces in previously rural or undeveloped land. Urban sprawl is often characterized by low-density development, car dependency, and a staggered layout that can impact the environment and quality of life for residents.

In contrast, urbanization refers to the increasing population concentration within urban areas, while city planning involves the organization and design of urban spaces to facilitate optimal living and working conditions. Rural development focuses on improving the economic and social conditions of rural areas, often through agriculture and infrastructure enhancements. These terms do not specifically capture the nature of a city's physical expansion into surrounding countryside land, making urban sprawl the most accurate choice.