House of Representatives: All 435 seats will be voted on. The Senate: 35 seats will be voted on (33 regular seats and 2 special elections). Gubernatorial elections: held in 36 states. The US Senate has a total of 100 senators; That is, 2 people from each of the 50 states. But unlike the House of Representatives, the tenure of senators is 6 years, and every two years only about a third of the seats are up for election.