I can't speak for the other cities, but the 2 in Chicago come as no surprise to me.
#1 on the list is on the west side, northwest of Rush Presbyterian Hospital, nope I don't want to go there. Its supposed to be one of those areas where they are trying to 'regentrify' the area, but I'm not moving there anytime soon.
#18 is just across the expressway from the old Comisky Park (White Sox) stadium and was the former site of a huge federal housing project called the Robert Taylor Homes. The area is one that I occasionally drive through (along the south edge) to get to Chicago's Museum of Science and Industry, or to the University of Chicago Hostpital/Campus, both of which are due east of the south edge of that area. Generally people are strongly advised to stay on the main road, windows rolled up, doors locked when transiting to where they are going.