There are thirteen.
Riverside Martin & Son Carriage
Repair Franklin Hostel
Britt's Sandwich Shop
Downtown Bus Station
Martin & Son Carriage Repair
These buildings should be preferred in buying Joints because the Public is more likely to wander in. Getting the Public into other Joints depends on a wink or neglect by your opponents.
The downside is that the Cops, starting at the local subway station, can get into these buildings in one turn too. Never fear! You will profit from Organized Crime for at least one player-turn. Be sure to improve your One-Jump Joints to level 2 or higher, so that a police raid won't disrupt ownership.
The buildings shown in black are the grey, unownable ones. Only the foolish or desperate extortionist would ply his trade in such a place -- right under the nose of (and one jump away from) the coppers!