In 1786, after General Washington ensured that Trenton would not be the national capital, and before Washington D. C. was created, a petition was circulated around among the leaders of Burlington and Hunterdon Townships. The petition called for the creation of the City of Trenton. Unlike its original hamlet configuration, the City of Trenton would not be allowed to act as its cousins of the time, creating the necessary government and community atmospheres of the cities of the 18th century.

This petition failed, but a compromise struck in the political manner of the day did create the Borough of South Trenton. This new borough cut between Hunterdon and Burlington and made for interesting political discontent. Unhappy with the 50 year old system of the 13 original New Jersey counties, the state legislature saw the new Borough as the starting point of a new county - one that would balance the power of the more northern Hudson county, while still enabling the southern counties a powerful voice in the state legislature.

In 1838, twenty three years before the Civil War, the New Jersey state legislature decided to redraw its county lines. Increasing the colonial 13 counties to a more modern 15 counties balanced the political powers of the day. Unhappy with the odd number of representatives in the county system, the state legislature created Mercer County.

The new county, which encompassed Princeton and Trenton, was carved out of parts of Hunterdon, Burlington, Middlesex, and Somerset counties. This was the birth of modern day Mercer County.

The name of Mercer was given to land in honor of General Hugh Mercer, a Revolutionary General who fell at the Battle of Princeton.

Trenton once again became a seat of power; this time as the county seat. The prosperity that the region was about to enjoy could never have been imagined at this time, but the work that was done in 1838 led to the creation of one of the most powerful and economically important cities in 19th and early 20th century America. Mercer County, it seems, has always been the place where history is made, and adventure takes place.