Suffolk County Executive Steve Bellone is running for reelection.
He announced his bid for a third term Sunday in Hauppauge.
Bellone has focused much of his tenure on transit improvements, the development of downtowns, and expansion of the county's sewer system.
His Republican opponent in November will be John Kennedy, the Suffolk County comptroller.
If he wins, it would be Bellone's last term. Suffolk has a 12-year limit on county executive terms.