[6] The densely populated district is one of the wealthiest in the state, with the highest equalized property value and income on a per capita basis.

[7][8] For the 2024-2025 session, the 21st legislative district of the New Jersey Legislature is represented in the State Senate by Jon Bramnick (R, Westfield) and in the General Assembly by Michele Matsikoudis (R, New Providence) and Nancy Munoz (R, Summit).

[11] In the next redistricting in 1991, a major change occurred to the district's boundaries: It now consisted of northern Union County from Roselle Park and Union Township, then north into the west side of Essex County from Millburn to North Caldwell and Cedar Grove.

[12] After a single term in the Senate, Thomas G. Dunn was dropped by the Union County Democrats in 1977 and was replaced on the party line by Linden Mayor John T.

[16] Joel Weingarten was elected to the Assembly in a November 1996 special election in which he defeated Democratic candidate Robert R. Peacock to fill the one year remaining on the vacant seat of Monroe Jay Lustbader, who had died in office in March 1996.