1) The slavery rates were much lower in South Jersey during the first three generations of the life of the nation (1790 to 1860). At the beginning of this period 92.6% of New Jersey's slaves were in the northern counties. By 1840 it was over 99%.
2) The 1860 popular vote for Lincoln in the Southern Counties as a whole was 55%, but was only 45% in the Northern Counties.
Totally off the radar, but of interest, an article that I read this morning has to do with the town of Baarle-Nassau/ Baarle-Hertog. It lies within the boundaries of the Netherlands, but because of a history dating back to feudal customs of the Middle Ages, the borders of Belgium and the Netherlands zig-zag through the area. It makes New Jersey's divide pale in comparison! Many of the borders even go through houses and bedrooms! Click on the picture to read the article.
The above video takes about 5 seconds before playing.