Public administrators are increasingly using social media in their day-to-day activities and duties. Despite the increased use of social media by public officers, there have not been studies that have investigated how this is affecting their day-to-day work. The aim of the study, from this perspective, was to identify the use of social media within public administration domains and in the community in a bid to document the lessons learnt and to inform improved integration of social media among public officers such as the chiefs and ward administrators. The study first aimed to investigate why public administrators are adopting social media to mobilize communities and in the improvement of security. The study also sought to examine ways in which social media is used to mobilize and enhance security in communities and the impact on community and security movement in Umoja Ward, Lanet Sub County, Nakuru County. The study was based on the diffusion of innovation theory that explains how technology is adopted in organizations while the new public management theory advocates for application of private sector concepts such as use of social media for public administration. A descriptive research design was applied in this study. This helped to answer questions concerning the tools used in social media and their impact on community mobilization and security enhancement. The public and citizens in Lanet Sub County were the target population. The target population was the area chief, assistants, police officers, support personnel and 28,012 adult residents. The study‟s sample size was 68 participants. Data collection was carried out using questionnaires for officials and for citizens. The study used descriptive and content analyses were undertaken according to the objectives of the study.