Midsalip is a landlocked municipality in the coastal province of Zamboanga del Sur.

The municipality has a land area of 161.56 square kilometers or 62.38 square miles which constitutes 3.60% of Zamboanga del Sur’s total area. Its population as determined by the 2020 Census was 33,711. This represented 3.21% of the total population of Zamboanga del Sur province, or 0.87% of the overall population of the Zamboanga Peninsula region. Based on these figures, the population density is computed at 209 inhabitants per square kilometer or 540 inhabitants per square mile.