Border insecurity has become a major phenomenon in most sub-Saharan African countries including Nigeria. Virtually all regions or states in Nigeria are prone to irregular migration occasioned by border insecurity or management. This has culminated into security challenges such as the Boko-Haram insurgency, armed banditry, among others. Kwara State, one of the 36 states in Nigeria, has been engulfed in security challenges due to its border porosity. The State has been experiencing migrant-induced organised crimes such as kidnapping in some border communities. While there are many theoretical and empirical studies on border security, irregular migration and security challenges in Nigeria, only a few studies have been conducted in Kwara State, Nigeria perhaps because it is recent development. Besides, even the few existing studies on it were theoretical and anecdotal. To fill this gap, this study examines the impact of border insecurity on irregular migration, and how irregular migration brings about human security challenges. The study anchored on human security. This study adopted a qualitative research method (mono-method with the use of in-depth interview). The target populations are members of the communities in border areas, relevant law enforcement agencies and government officials. Purposive sampling technique was used to select 11 border communities in Baruten Local Government Area of Kwara State, Nigeria. Also, a purposive sampling technique was used to select 10 participants (including law enforcement agents, community, religious and opinion leaders) from each of the selected communities (n = 110). In-depth interview was used to collect qualitative data. Thematic analysis was used to analyse the data. The study found that irregular migration thrived in the border communities because of the presence of ungoverned forests/borders, and this has implications on human security. However, irregular migrants might be both victims and perpetrators of human security challenges in the host communities. Therefore, the government should extend security infrastructure to police/govern the illegal borders in the study area.