Zone 4 Poblacion, formerly Sagapan, is a barangay in the municipality of Iba, in the province of Zambales. Its population as determined by the 2020 Census was 443. This represented 0.80% of the total population of Iba. Situated at approximately 15.3260, 119.9788, in the island of Luzon. Elevation at these coordinates is estimated at 12.2 meters or 40.0 feet above mean sea level.