African countries have a long history of internal migration since the colonial era where evidence has showcased the contributions of migrants to development from economic to environmental. Internal migration patterns of today are not governed by policies but are indirectly and directly influenced by the existing structures and initiatives operational in different parts of the country that attract and/or push migrants to move to a specific destination. Internal migration increased in Kenya after independence in 1962 when colonial policies-controlled internal migration was removed as rural dwellers were attracted to cities due to the social services, employment, and other opportunities it provided to them and their households. This created a culture of migration that still exists in present-day Kenya, which is currently dominated by the youth. The need to refocus attention on internal migration dynamics is key for planning and development purposes from national to county level. This chapter focusses on internal migration dynamics in Kenya of the youth and their contribution to the development of sustainable counties drawing evidence from existing studies in youth migration in Kenya including a recent study by the African Migration and Development Policy Centre (AMADPOC) on Youth, Employment and Migration in Eastern and Southern Africa (YEMESA) outlining the importance of internal migration in national development planning to achieve some goals set in the Sustainable Development Goals Target 11 on inclusive cities.