Congrats Tom, I take it your picture is your avatar. Although not a rare sighting, they are not common. The Cape May Hawk Watch recorded 13 in 2017, the top count was 38 in 1996. It is very late for migration, which occurs in Oct/Nov. The one you saw may have found a home in NJ. I do not know of anyone that is keeping sighting records as it is not endangered, but you could fill out a report at this link;
http://www.state.nj.us/dep/fgw/ensp/rprtform.htm
or contact Kathy Clark of the Endangered and Nongame Species Program at Tuckahoe WMA.
This link is from HawkCount for NJ Audubon's Cape May Hawk Watch totals, the watch begins 9/1 and ends 11/30 each year at Cape May Point SP.
http://hawkcount.org/month_summary.php?rsite=328&ryear=2017&rmonth=11
There are a number of watches in the state, the link shows the list. Each keeps a separate count.
http://hawkcount.org/sitesel.php?country=USA&stateprov=New Jersey