As of the 2019 federal election, the constituency has 429,516 voters who elect 16 National Council members.
The constituency of Aargau was first created in 1848 to represent the canton of Aargau in the National Council.
At that time, nine seats in the National Council was allocated to the canton.
After proportional representation was adopted in 1918, the constituency was formed again through a National Council election law on 14 February 1919.
[2] It was allocated 12 seats in the National Council in 1919.