Americans will go to the polls tomorrow, what is at stake in these elections?
Americans are voting for all 435 seats in the House of Representatives, and 35 of the 100 Senate seats.
Governors are also being chosen in 36 out of 50 states. In Florida and Georgia, Democrat candidates are hoping to become their states’ first African American governors.
Democrats are confident of overturning the Republican majority in the House, but a booming economy is likely to favour the Republican incumbents.
But in the Senate, most of the seats being contested are currently held by Democrats. Some are considered vulnerable, as they are in states won by Mr Trump when he was elected in 2016.
So, the Republicans could potentially increase their majority in the Senate.
But even losing the House would be a blow for Mr Trump, as the situation would create a potential for legislative gridlock and even government shutdown.
The first polls close at 23:00 GMT (18:00 EST) on Tuesday and while it will take some time to see the full picture emerge, there are some races worth keeping an eye out for.
Democrats need to gain 23 seats in order to take the House – take a look at vulnerable House seats which Republicans currently hold in and around Orange County in California, for example.
In the Senate, Democrats have high hopes of gaining Republican-held seats in Arizona and Nevada.
They would need to make a gain of two seats to win control the Senate – but also risk losing their own Senate seats in North Dakota and Missouri.
The races for governor in Florida and Georgia are also too close to call.