Congress is made up of the (a) Senate and the (b) House of Representatives.
There are 100 seats in the senate; currently 51 are Republican held, 47 are held by Democrats, and 2 are held by Independents.
On November 6th, 35 of the seats will be up for grabs (standard 33, plus 2 special election seats (seats vacated) for a total of 35). Democrats currently hold 26 of the seats up for grabs.
Various outlets are predicting that 21 of the available 35 will well-likely go to Dems. It is believed that 8 will likely go to Republicans. That leaves 6 races that are believed to be a toss-up.
The predicted toss-ups are:
Democrats will need to maintain their seats and pick up new ones in order to gain control of the senate.
All of the 435 congressional district seats will be sent to election this November 6. To have majority voting or representation power - a part needs 218 seats.
It is predicted that about 29 of the total 425 could swing either way. That prediction sees 209 likely going to Dems, and 198 likely going to Republicans.
Currently, Republicans hold majority in the US House with 235 seats, whereas Dems hold 193; - 7 seats currently are vacant.
The race for PA state Governor features incumbent Tom Wolf (Dem) against Scott Wagner (Rep), and a pair of additional Rep write-ins.
US Senate for PA race features incumbent Bob Casey (Dem) against Lou Barletta (Rep), and a green and libertarian long-shot.
US House for PA (District 10 - York City, etc.) features incumbent Scott Perry (Rep) against George Scott (Dem). District 11 (Lancaster) features incumbent Lloyd Smucker against Jess King (Dem).
PA Senate for 28th District features (current state representative) Kristin Phillips-Hill (Rep) against Judith Higgins (Dem).
PA House Representative for the 95th District is Carol Hill-Evans - uncontested.