As of the 2010 United States Census, the district had a population of 210,628, of whom 159,952 were of voting age. The racial makeup of the district was 111,978 White, 54,600 African American, 1,192 Native American, 9,387 Asian, 46 Pacific Islander, 25,490 from some other race, and 7,898 from two or more races. Hispanic or Latino of any race were 89,691 of the population. The district had 129,444 registered voters as of February 1, 2020, of whom 44,375 were registered as unaffiliated, 72,263 were registered as Democrats, 10,494 were registered as Republicans, and 2,312 were registered to other parties. The district has a higher-than-average percentage of residents who are foreign born, Hispanic and African American. The number and percentage of registered voters is lowest in the state. Registered Democrats outnumber Republicans by a better than 4 to 1 margin, with Republican registration percentage one of the lowest of any district statewide.
When the 40-district legislative map was created in 1973, the 20th was a central Union County-based district including Westfield, Garwood, Cranford, Roselle, Roselle Park, Union Township, and Hillside Township. In the 1981 redistricting, the 20th District received completely new municipalities in eastern Union County including Elizabeth, Linden, Rahway, and Carteret in Middlesex County, New Jersey. Carteret was removed from the district following the 1991 redistricting but Roselle was added from the 21st District. 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 removed Linden and Rahway and added Kenilworth and Union Township. As part of the 2011 apportionment, Hillside was added from the 29th District, while Kenilworth Borough was shifted to the 21st District.
Election history
In the 1973 State Senate race, Alexander J. Menza defeated incumbent Republican Frank X. McDermott, who had served 10 years in office, helping the Democrats gain control of the state legislature for only the third time in the 20th century. In the 1975 elections, McDermott made a comeback and won a seat in the Assembly. In the 1977 Senate race, Menza chose not to run for re-election. McDermott ran again for the seat, losing to Democrat Anthony E. Russo. In redistricting following the 1980 United States Census, C. Louis Bassano was shifted to the 21st Legislative District, where he ran for the State Senate seat. Chuck Hardwick was also shifted to the 21st District, where he would win the Assembly seat. With both seats open, Democrats Thomas J. Deverin and Raymond Lesniak, who had both previously served as representatives of the 21st District, won in the Assembly. In the Senate race that year, Anthony E. Russo was also shifted to the 21st District and was replaced by John T. Gregorio, an incumbent Democrat who was shifted from the 21st District. Gregorio was forced to resign in 1983 after being convicted of conspiracy for concealing his ownership of two go-go bars that were operated by his son. In a June 1983 special election, Lesniak won the seat Gregorio was forced to vacate. In turn, another special election was held in August 1983 to fill Lesniak's vacancy, a race that was won by Thomas W. Long. After five terms in the 20th District, Thomas J. Deverin was relocated to the 19th Legislative District in 1991, with redistricting following the 1990 Census tending to favor Republicans. In the 1991 Republican landslide, the 20th bucked the trend, with incumbent George Hudak and Elizabeth Mayor Thomas G. Dunn narrowly holding on to the seats for the Democrats. Hudak and Dunn did not run for re-election in 1993. In the 1993 election, two former Union County Freeholders, Joseph Suliga and Neil M. Cohen were elected. Suliga represented the district in the Assembly until 2002, when he was shifted to the 22nd Legislative District as part of the 2001 redistricting, and was elected to the State Senate.Joseph Cryan was elected to the Assembly in 2001, filling Suliga's Assembly seat. Cohen resigned from the Assembly on July 24, 2008, after images of child pornography were found on his state-issued computer. Democratic committee members from the district selected Annette Quijano to fill Cohen's vacancy. Joseph Cryan stepped down on January 4, 2015 to become Union County Sheriff. The Union County Democrats selected Roselle Mayor Jamel Holley as his replacement on January 21, 2015. Senators and Assembly members elected from the district are as follows:
