Republican senator Randy Vulakovich of the 38th district was the only incumbent to be defeated in the primary elections, losing to Jeremy Shaffer, who in turn lost to Democratic candidate Lindsey Williams in the general election.

Two other Republican incumbents – Thomas J. McGarrigle and John Rafferty Jr. – were also defeated in the general election by their Democratic challengers (Timothy P. Kearney and Katie Muth, respectively).

In the 10th district, Republican Chuck McIlhinney chose to retire, and his seat was won by Democrat Steve Santarsiero, while in the 12th district, Republican Stewart Greenleaf retired and was replaced by Democrat Maria Collett.

Ten district races had winning margins of less than 15%: Democrat Lindsey Williams defeated Republican Jeremy Shaffer in the 38th District, a seat previously held by Republican Randy Vulakovich.

[5] This announcement came after Williams provided proof that she had accepted a job in Pennsylvania on November 2, 2014.