Thurgau, or Thurgovia, is an eastern canton, named after the river Thur that runs through it. It was first made into a canton in 1798 after the formation of the Helvetic Republic, but its territories were incorporated in the Swiss Confederacy in the mid 15th century. It borders Lake Constance to the north. It's a mostly Protestant (45%) canton where 20% of its population are foreigners.