The 4th Legislative District is located in the central-eastern portion of Suffolk County encompassing the central section of Brookhaven Town. The district includes:
The Brookhaven Town portion of Ronkonkoma
Centereach
Coram
Farmingville
Holbrook
Holtsville
Lake Grove
Lake Ronkonkoma
Medford
Port Jefferson Station
Selden
It consists of fifty-three (53) election districts with approximately 80,000 residents and 51,373 registered voters.