Twenty of the country's cantons send two Councillors each. The smaller cantons of Obwalden, Nidwalden, Basel-Stadt, Basel-Landschaft, Appenzell Ausserrhoden and Appenzell Innerrhoden send one Councillor each. The latter six have traditionally been considered "half-cantons", because of their smaller size in area and in population, but in practice operate as full cantons.
The Councillors serve for four years, and are not bound in their vote to instructions from the Cantonal authorities. Under the Swiss Federal Constitution, the mode of election is left to the cantons, the proviso being that it must be a democratic method; however, all cantons now provide for the councillors to be chosen by popular election. In all Cantons except for Zug and Appenzell Innerrhoden, the Councillors are elected concurrently with the members of the National Council. In the canton of Appenzell Innerrhoden the representatives are elected by the physically convened popular assembly (Landsgemeinde). With the exception of the Canton of Jura, where a proportional representation election system is used, the representatives are elected by majority vote.
There are currently (2008) 10 women in the Council of States (22%).
| Abbr | Canton | Seats | Population ¹ | per seat | ² |
|---|---|---|---|---|---|
| ZH | Zurich | 2 | 1,228,600 | 614,300 | 1.0 |
| BE | Bern | 2 | 947,100 | 473,550 | 1.3 |
| VD | Vaud | 2 | 626,200 | 313,100 | 2.0 |
| AG | Aargau | 2 | 550,900 | 275,450 | 2.2 |
| BL | Basel-Landschaft | 1 | 261,400 | 261,400 | 2.4 |
| SG | St. Gallen | 2 | 452,600 | 226,300 | 2.7 |
| GE | Geneva | 2 | 414,300 | 207,150 | 3.0 |
| BS | Basel-Stadt | 1 | 186,700 | 186,700 | 3.3 |
| LU | Lucerne | 2 | 350,600 | 175,300 | 3.5 |
| TI | Ticino | 2 | 311,900 | 155,950 | 3.9 |
| VS | Valais | 2 | 278,200 | 139,100 | 4.4 |
| SO | Solothurn | 2 | 245,500 | 122,750 | 5.0 |
| FR | Fribourg | 2 | 239,100 | 119,550 | 5.1 |
| TG | Thurgau | 2 | 228,200 | 114,100 | 5.4 |
| GR | Graubünden | 2 | 185,700 | 92,850 | 6.6 |
| NE | Neuchâtel | 2 | 166,500 | 83,250 | 7.4 |
| SZ | Schwyz | 2 | 131,400 | 65,700 | 9.4 |
| AR | Appenzell Ausserrhoden | 1 | 53,200 | 53,200 | 11.5 |
| ZG | Zug | 2 | 100,900 | 50,450 | 12.2 |
| NW | Nidwalden | 1 | 38,600 | 38,600 | 15.9 |
| SH | Schaffhausen | 2 | 73,400 | 36,700 | 16.7 |
| JU | Jura | 2 | 69,100 | 34,550 | 17.8 |
| OW | Obwalden | 1 | 32,700 | 32,700 | 18.8 |
| GL | Glarus | 2 | 38,300 | 19,150 | 32.1 |
| UR | Uri | 2 | 35,000 | 17,500 | 35.1 |
| AI | Appenzell Innerrhoden | 1 | 15,000 | 15,000 | 41.0 |
| Overall | 46 | 7,261,200 | 157,852 | 3.9 | |