Angus King, independent

• Age: 74

• Lives in Brunswick and Washington, D.C.

• Married, with five adult children and six grandchildren

• King is a lawyer-turned-businessman and former public television host who served as Maine’s governor for two terms from 1995-2003. After that, he left politics but stayed active in both the business and nonprofit worlds. He was elected to the U.S. Senate in 2012 with 53 percent support in a three-way race, replacing Olympia Snowe, a Republican who unexpectedly decided not to seek re-election after three terms.

Eric Brakey, Republican

• Age: 30

• Lives in Auburn

• Married, no children

• Brakey majored in theater in college and worked as an actor for a short time after graduation. He rose to prominence in the state party in 2012 at the convention, when delegates of then-presidential hopeful Ron Paul won the Maine caucuses. He won election to the Maine Senate in 2014, beating an incumbent Democrat, was re-elected in 2016 and served as chairman of the Health and Human Services Committee. In addition to being a lawmaker, Brakey has worked for his family’s Ohio-based energy business.

Zak Ringelstein, Democrat

• Age: 32

• Lives in Yarmouth

• Married, with two young children

• Ringelstein has never run for or held public office. His background is in education, both as a teacher and as an entrepreneur who founded a company that provides online lesson plans and other resources to school districts.