This study developed and validated a measurement-informed MATLAB/Simulink harmonic propagation model for a practical 33 kV distribution network using the Ungwan Boro feeder in Kaduna Metropolis, Nigeria, as the study network. Field-derived feeder characteristics, transformer impedance, load current profiles, and harmonic spectra were used to parameterise the model, which incorporated frequency-dependent network impedances, nonlinear loads, and harmonic current injections. Simulation results revealed pronounced current distortion dominated by the 3rd, 5th, and 7th harmonics. At the Ardo Substation, the simulated current total harmonic distortion (THD) of 27.69% compared closely with the measured value of 27.95%, corresponding to a percentage deviation of 0.94%. At the Reg Substation, the simulated spectrum reproduced the dominant harmonic orders identified in the corresponding field-derived data. The combined quantitative and spectral agreement demonstrates the model's ability to reproduce the principal harmonic characteristics of the investigated feeder. The validated framework provides a measurement-informed computational basis for harmonic propagation analysis and subsequent investigation of harmonic-related phenomena and mitigation strategies.