Sustainable city growth necessitates sound political decisions. Owing to ineffective policies, the land price increments have had a significant impact on immigration settlements. Scholars have studied city immigrant settlements without mentioning rising land prices as a major driver of illegal settlements. This study explores the influence of the long-term increase in land prices on immigrant settlement, by employing a panel cointegration model and the city-level panel data of Abomey-Calavi from 1992 to 2012. Increments in land prices are found to be correlated with both internal and external immigrants. Rising land prices hamper formal immigrant settlement. City growth may suffer significantly as the number of immigrants may double by 2030. However, implementing a novel land banking policy in urban planning, may help control land price spikes and limit illegal settlements. The findings advocate for a discussion on affordable land prices at the Sustainable Development Goals (SDG11) summit.