The municipality is lying on the northeastern part of the province, located 8 kilometers from Dipolog City. It is bounded in the northwest by the city of Dipolog; in the northeast by the city of Dapitan, in the south by the municipality of Sergio Osmena, in the east by the municipality of Piñan and in the southwest by the municipality of Katipunan, with a geographic coordinates of 8o 31’ 59” N, 123o 22’ 0” E.
Polanco is generally plain especially in the rice land areas. Some parts are slightly mountainous like barangays of Linabo, Maligaya, Milad, De Venta Perla and Dangi. Two prominent rivers traverse the length of the municipality; Layawan River and Dipolog River, both rivers flow into the Sulu Sea at Poblacion of Dipolog City situated along the river banks are the corn granaries of the municipality.
The municipality has a total land area of 22,532.9104 hectares and classified as agricultural land. Of the thirty (30) barangays, barangay of Dansullan recorded huge landholding area of 2,618.569 hectares followed by barangay Milad and barangay De Venta Perla with 1,773.2156 hectares and 1,744.2534 hectares, respectively.
The two (2) barangays considered as central business district in the municipality shared a small landholding area of 232.9967 hectares and 116.0710 hectares in Barangays of Poblacion North and Poblacion South, respectively. Polanco is divided into thirty (30) barangays. This is further divided into one hundred seventy one (171) puroks.