Trenton’s flag is divided in half, blue at the hoist and gold at the fly. In the center is the city seal in gold. The seal, nearly the height of the flag, has a white field bordered by a fancy blue ring. In its center is a blue shield with three wheat sheaves, 2 over 1, in buff. From the upper corners of the shield hang tassels or chains. Above the shield on a heraldic wreath is a nag’s head, in profile facing the hoist, and encircling the coat of arms is SEAL OF THE CITY OF TRENTON, with 1792 below.
The nag’s (horse’s) head, which also appears on the state seal, and wheat sheaves represent agriculture, an important economic resource when the area was first settled by English Quakers in 1679. They are also appropriate symbols for the capital city of New Jersey, “The Garden State”. The state legislature granted the city’s charter in 1792. Since 1909, blue and gold have been the city’s official colors; buff has been a traditional color of New Jersey since the 1700s.
Although not directly related to the flag, the first city seal bore just one wheat sheaf and CITY OF TRENTON with the city motto E PARVIS GRANDES (“Out of the Small [come] the Great”) around the circumference. The seal was later changed, adding two more wheat sheaves, the nag’s head, and the year 1792, eliminating the motto.
Before the adoption of this official flag, the city had used a similar unofficial flag for a number of years, except the city seal was centered on the blue stripe at the hoist.
Source: John M. Purcell: American City Flags