When the 40-district legislative map was created in 1973, the 16th district consisted of all of Somerset County (except
Franklin Township and Manville and included Readington in Hunterdon County, and
Morris County's Chester
Borough and
Township and
Mendham Borough. Following the 1981 redistricting, the district largely remained the same with Rocky Hill and Millstone boroughs being shifted to the
14th district, Readington trading with
East Amwell Township to be Hunterdon's lone municipality in the district, and the removal of the Chesters to add
Mendham Township in the Morris County portion. Changes to the district made as part of the New Jersey Legislative
redistricting in 2001, based on the results of the
2000 United States census, added Bound Brook (from the
17th legislative district) and removed Franklin Township (to the 17th legislative district). Prior to the 2011 decennial reapportionment, as part of the 2001 apportionment, the district consisted of the
Somerset County municipalities of
Bedminster Township,
Bernards Township,
Bernardsville Borough,
Bound Brook Borough, Branchburg Township,
Bridgewater Township,
Far Hills Borough, Hillsborough Township, Manville Borough, Millstone Borough, Montgomery Township,
Peapack-Gladstone Borough,
Raritan Borough, Rocky Hill Borough, Somerville Borough, and
South Bound Brook Borough and the Morris County municipality of Mendham Borough. In 2011, Coyle declined to run for re-election as her Bernards Township home was moved out of the district and the seat was won by
Jack Ciattarelli, a member of the Somerset County
Board of Chosen Freeholders. After Peter Biondi died two days after winning re-election, Ciattarelli was appointed to complete Biondi's unexpired term ending January 10, 2012. Biondi's seat was then vacant again until Readington Township committeewoman
Donna Simon was sworn in on January 30, 2012 as an interim appointee pending a November 2012 special election where she defeated Marie Corfield by just under 1,000 votes out of 91,000 ballots cast. Simon & Ciattarelli were both re-elected, but Simon was defeated in 2015 in a close race by Democrat Andrew Zwicker in 2015. Initial counts showed Simon ahead of Zwicker on the night of the election (Ciattarelli was far enough ahead in first place to be ensured victory) but following the counting of
provisional ballots, Simon conceded November 16. ==Election history==