Bolken is a municipality in the district of Wasseramt in the canton of Solothurn in Switzerland. Bolken is first mentioned in 1429 as ze Bolliā¦Bolken is a municipality in the district of Wasseramt in the canton of Solothurn in Switzerland. Bolken is first mentioned in 1429 as ze Bollikon. Bolken has an area, as of 2009, of 2.12 square kilometers. Of this area, 1.37 km² or 64.6% is used for agricultural purposes, while 0.46 km² or 21.7% is forested. Of the rest of the land, 0.26 km² or 12.3% is settled, 0.04 km² or 1.9% is either rivers or lakes.