Analysis of Population Growth Models and Urban Expansion in Abuja, Federal Capital Territory

This study analyses mathematical population growth models in relation to the patterns of urban expansion observed in Abuja, Federal Capital Territory, Nigeria's purpose-built national capital, which has experienced some of the fastest rates of urban population growth on the African continent since the early 2000s. The study evaluates the fit of exponential, logistic, and Gompertz growth models to historical population data for the FCT sourced from the 2006 and 2023 national census figures, supplemented by annual population estimates published by the National Population Commission. Model parameters are estimated using nonlinear least squares regression, and forecasts are generated for the population of Abuja through to 2035 under each model specification. The implications of the population projections for residential land demand, water supply infrastructure, and transportation network capacity are discussed using secondary data on urban infrastructure provision from the FCT Administration. Results indicate that the logistic model, which accounts for a carrying capacity constraint, provides a better long-range fit to Abuja's growth trajectory than the exponential model, which significantly overestimates future population in scenarios beyond 2030. The Gompertz model offers intermediate performance. The study contributes a quantitatively grounded analysis to the urban planning discourse in Abuja and recommends the use of logistic projection models in FCT masterplanning exercises. Keywords: population growth models, logistic growth, Gompertz model, urban expansion, Abuja