morris county is a county in the u.s. state of new jersey, close to new york city. as of 2017, there was 499,693 people living in the county. this made it the 10th-most populous county in new jersey. the county seat is morristown. the place where most people live at is parsippany-troy hills township, with 53,238 people, while the largest place is rockaway township, at .