Reinach covers an area of 700 hectares. The River Birs flows through it. Reinach's highest point is 371 m above sea level and the lowest 274 m above sea level. The community has almost 19,000 inhabitants and is thus the most populous in Canton Basel-Land. Various motorway accesses and a well-developed public transport network make the journey into the city centre, but also to the main railway station (Bahnhof SBB) and the EuroAirport Basel-Mulhouse, a short one.