Oberwil is a municipality in the district of Arlesheim in the canton of Basel-Country in Switzerland. Oberwil is first mentioned around 1102–110…Oberwil is a municipality in the district of Arlesheim in the canton of Basel-Country in Switzerland. Oberwil is first mentioned around 1102–1103 as Oberuuilre. Oberwil has an area, as of 2009, of 7.88 square kilometers. Of this area, 3.47 km² or 44.0% is used for agricultural purposes, while 1.54 km² or 19.5% is forested. Of the rest of the land, 2.82 km² or 35.8% is settled, 0.03 km² or 0.4% is either rivers or lakes and 0.02 km² or 0.3% is unproductive land.