Miagao lies between 10° 36' 44" N latitude and 122° 06' 39" and 122° 17' 30" E longitude. A later section lists 10° 38' 26.4" N latitude and 122° 14' 6.3" E longitude.
Miagao is one of the seven towns comprising the First District of Iloilo Province. It is situated 40 kilometers southwest of Iloilo City and 58 kilometers from San Jose, the capital town of Antique. Overlooking the island of Negros towards Sulu Sea or Panay Gulf, Miagao is bounded by:
- Igbaras to the northeast
- Guimbal to the east
- San Joaquin to the west
- Sibalom, Antique to the northwest
Land area and waters:
The municipality has a land area of 15,696 hectares or 156.96 square kilometers. The urban area composed of 22 barangays has an area of 1,852.55 hectares or 18.5255 square kilometers, while the remaining 97 barangays have a total area of 13,843.45 hectares or 138.4345 square kilometers. A later profile table lists 15,680.00 hectares total, 2,055.16 hectares urban, and 13,624.84 hectares rural.
The municipal waters serving as fishing ground for both migratory and endemic fish has an area of 48 square kilometers. Miagao's coastline stretches for 16 kilometers, spanning 22 barangays.
The inland bodies of water are composed of three main rivers, namely Tumagboc, Oyungan, and Bacauan. The other smaller rivers are Naulid, Oya-oy, and Narat-an. They all flow to the Panay Gulf. The Oyungan River has colored stones.
Topography:
Miagao is partly coastal and partly mountainous. In general, its terrain is rolling with mountain ranges serving as border between Miagao and part of the Province of Antique and other neighboring towns of Iloilo. The poblacion is situated on a hill overlooking the sea and public institutions are located on a plateau. The low and high mountains lying close to the river, plus the narrow coastal plains stretching 16 kilometers, are varied topographical features of Miagao.
Climate:
Miagao has two pronounced seasons: dry from November to April and wet during the rest of the year. The maximum temperature is 32.2°C and the minimum is 22.9°C. There are two prevailing winds: the southwest monsoon called “habagat” and the northeast monsoon called “amihan”.
Soil:
The soil consists of five major types: Alimodian clay loam, Sta. Rita clay, Umingan fine sandy loam, Alimodian soil undifferentiated, and beach sand.
Natural resources:
Miagao is rich in natural resources. It has vast forest reserves at Tabiac and Tulahong forestry areas. It has metallic and non-metallic reserves as indicated by grains of sand found on the beach lines. It has abundant source of ceramic clay used for potteries and mixtures of sand and lime structure called the Miagao Stone used as building material, like the one used in building the Miagao Church. It is also blessed with natural scenic attractions like Sinuhutan Cave, Danao Lake, Bugsukan Falls, rice terraces, and others.
Slope:
The municipality has five slope classifications ranging from 0°–30° slopes above sea level. The area marked A has a slope of 0°–3°; B 3°–7°; C 8°–13°; D 30°. The highest slopes are found in the mountain ranges that run from north to west of the municipality and the lowest slopes on the shoreline.
Barangays:
Comprised of 119 barangays, of which the page lists 25 as classified urban in one line and 22 urban in the tables, and 97 as rural barangays.