This action research investigated local histories and socio-cultural changes by examining local people’s lifestyles from the past to the present, including settlement and migration, livelihoods and local resources, community relationships, traditions, rituals, and adaptations of local people. The study also explored impacts on people and access to area development due to violence in the three restive southern provinces. The data were collected by interviewing local elderly and knowledgeable people. The findings were analyzed and presented chronologically. The study discovered the importance of Yalo in the past as a prehistoric community settlement due to suitable geographical conditions and fertile natural resources. The city was relocated several times in accordance with the evolution of transportation, convenient trade routes, and urbanization and urban development. Socio-cultural changes included administrative system and traditions and rituals due to technological advances and modernization. Changes in agriculture were from subsistence farming to single crop production because there was support from commercial development projects from the state. Vocational changes were from agriculture to wage earners and state employees due to investments of business operators and higher education. Furthermore, changes toward urbanization made social stratification clearer. The impact of political violence in the three restive southern provinces was on both local people and private agencies attempting to solve the problems. The main reason that local people began to believe in an increase in violence was from the wrong decision in making government officials use firearms to deal with the Sam Yaek Ban Niang incident on April 28, 2004.