Located in the canton of Aargau, the ‘Sisslerfeld‘, with just under 200 ha, is an area of economic development focus (ESP) of cantonal importance according to the cantonal structure plan. Combined with optimal use by high-value-added, low-emission businesses and a high density of jobs, this is aimed in particular at promoting the canton's economic attractiveness, innovation and competitiveness.

The area development of the ESP Sisslerfeld aims to develop a target image 2040+ with the help of a planning process - consisting of informal instruments (test planning) and formal instruments (regional sectoral plan and general land use planning) - and to establish the marketability and building maturity of the area. The project perimeter comprises the four site municipalities of Eiken, Münchwilen, Sisseln and Stein, as well as Bad Säckingen on a cross-border basis. TBF has been responsible for the overall project management of the area development since the kick-off in 2019.