Kölliken has an area, as of 2009, of 8.89 square kilometers (3.43 sq mi).
 Of this area, 2.92 km² (1.13 sq mi) or 32.8% is used for agricultural purposes, while 3.85 km² (1.49 sq mi) or 43.3% is forested.
  Of the rest of the land, 2.04 km² (0.79 sq mi) or 22.9% is settled (buildings or roads), 0.02 km² (4.9 acres) or 0.2% is either rivers or lakes and 0.01 km² (2.5 acres) or 0.1% is unproductive land.

Of the built up area, industrial buildings made up 1.7% of the total area while housing and buildings made up 11.8% and transportation infrastructure made up 6.9%.
 Power and water infrastructure as well as other special developed areas made up 2.0% of the area  Out of the forested land, 42.0% of the total land area is heavily forested and 1.3% is covered with orchards or small clusters of trees.
 Of the agricultural land, 21.9% is used for growing crops and 9.6% is pastures, while 1.3% is used for orchards or vine crops.
 All the water in the municipality is flowing water.

The municipality is located in the Zofingen district, along Kölliker creek on the western edge of the lower Uerkental.
 It consists of the linear village of Kölliken.
Kölliken has an area, as of 2009, of 8.89 square kilometers (3.43 sq mi).  Of this area, 2.92 km² (1.13 sq mi) or 32.8% is used for agricultural purposes, while 3.85 km² (1.49 sq mi) or 43.3% is forested.   Of the rest of the land, 2.04 km² (0.79 sq mi) or 22.9% is settled (buildings or roads), 0.02 km² (4.9 acres) or 0.2% is either rivers or lakes and 0.01 km² (2.5 acres) or 0.1% is unproductive land.
Of the built up area, industrial buildings made up 1.7% of the total area while housing and buildings made up 11.8% and transportation infrastructure made up 6.9%.  Power and water infrastructure as well as other special developed areas made up 2.0% of the area  Out of the forested land, 42.0% of the total land area is heavily forested and 1.3% is covered with orchards or small clusters of trees.  Of the agricultural land, 21.9% is used for growing crops and 9.6% is pastures, while 1.3% is used for orchards or vine crops.  All the water in the municipality is flowing water.
The municipality is located in the Zofingen district, along Kölliker creek on the western edge of the lower Uerkental.  It consists of the linear village of Kölliken.
Kölliken