This thesis proposes a geographical approach to public security, a very relevant topic both in the daily lives of many residents of metropolitan areas and in the political debate held throughout the country. The potentialities and limitations of building a public security governance that focus on the Baixada Fluminense, an important part of the Região Metropolitana do Rio de Janeiro (RMRJ), were analyzed, considering the functioning of the Conselhos Comunitários de Segurança (CCS) and police actions in the region. The procedures and techniques employed for the development of doctoral research broadly comprised bibliographical and documental surveys, in addition to the production of abundant empirical material. 66 minutes of meetings of the CCS of Baixada Fluminense were analyzed, in the period between July 2016 and June 2019; more than 15 interviews were conducted with police officers, permanent members of the aforementioned councils, a mayor and a municipal security secretary; 15 CCS meetings were monitored in situ, between August 2019 and July 2021; two extensive fieldworks were carried out: the first in the vicinity of the Arco Metropolitano (in Nova Iguaçu) and the other in Complexo do Roseiral (in Belford Roxo). In addition, 11 maps and 3 time series were produced on the incidence of violent lethality and street robberies and cargo thefts in the region studied, important strategic indicators for the Instituto de Segurança Pública do Rio de Janeiro (ISP). The research results show that CCS in Baixada Fluminense can become a vector for building public security governance, as long as the partnership is adopted as a preferred level of openness to popular participation in these spaces and socio-spatial differences are considered when the elaboration of public policies aimed at reducing the incidence of crime and also the feeling of insecurity.