NJ is not the most urban state. NY, NV, UT, IL, and CA are all higher, mainly due to one huge urban area in each state. But in terms of density, all I can find is 1990, and NJ really is the number one, by a lot. Average of 402 per square kilometer, versus 370.8 in RI, 296.4 in MA, 262.0 in CT. On the other end, there's 1.8 in WY, 2.1 in MT, 0.4 in AK, 4.7 in ID. Even CA is only 73.7. Overall, US is 27.2.