Each of the three qualified parties in Maine (Democratic, Green Independent and Republican) will hold a primary election on June 10. Voters will be asked to choose party nominees for the U.S. Senator, Representative to Congress District 1, State Senator District 20, Representative to the Legislature District 61, Judge of Probate, and County Commissioner District 1 elections in November.

Senator Susan Collins is running unopposed in the Republican primary for U.S. Senate, the seat she currently holds. On the Democratic ballot for U.S. Senate, Rep. Thomas H. Allen, Portland, faces Thomas J. Ledue, Sanford.

Six Democrats are vying for the nomination in the race for Representative to Congress District 1, the seat currently held by Tom Allen: Michael F. Brennan, Portland, Adam R. Cote, Portland, Mark W. Lawrence, South Berwick, Stephen J. Meister, Winthrop, Chellie Pingree, North Haven, and Ethan King Strimling, Portland, all appear on the June ballot. For the Republican race for Congress District 1, Peter C. Scontras faces Charles E. Summers, Scarborough, for a place on November's ballot.

Democratic and Republican candidates for State Senator, Representative to the Legislature, and Probate Judge on the June 10 ballot are all running unopposed. The only other contested seat is for the Republican candidate for County Commissioner District 1. In that race, Lynn Gilley Orne, Southport, faces Jay D. Warren, Boothbay Harbor. David Taylor, Boothbay Harbor, runs unopposed for the Democratic place on the ballot for County Commissioner.

No Green Independent candidates are running in the primary election, but voters may write in names for any candidate of their choice.

One must be enrolled in a party to participate in June's primary election. Un-enrolled persons may enroll in a party at any time, including Election Day, by completing and filing out an enrollment application with the municipal registrar. Anyone who wishes to change enrollment from one party to another must file an application by Friday, May 23 in order to vote in the new party for the June 10th primary elections.