The responsibility of whoever owns or controls property for injuries caused by its condition - the slip on the wet floor, the broken stair, the unlit car park - and the rules that make the visitor's reason for being there matter.
Premises liability is the branch of negligence law that applies when a person is injured by the condition of land or a building: a spill left on a shop floor, ice on a walkway, a stair tread that gives way, a balcony rail that fails, inadequate lighting or security where an assault was foreseeable. The claim is against whoever owned or, more precisely, controlled the property at the time - which for leased premises can be the tenant, the landlord, a management company or all three, depending on who was responsible for the part of the property where the injury happened.
What the possessor owed depends, in most states, on why the injured person was there. A customer or someone present for the possessor's business (an "invitee") is owed the highest duty: reasonable inspection of the premises and repair or warning of dangers the possessor knew about or should have found. A social guest (a "licensee") is generally owed a warning of dangers the possessor actually knew about. A trespasser is owed little beyond a duty not to injure wilfully, with important exceptions for children drawn onto land by something attractive and dangerous. A number of states have collapsed these categories into a single standard of reasonable care that treats the visitor's status as one factor among several.
The contested question in most cases is notice: whether the hazard existed long enough, or recurred often enough, that a reasonable possessor would have found and fixed it. A spill that happened moments earlier is not the shop's fault; a spill that had been tracked through by other customers usually is. The injured person's own carelessness is weighed under the state's comparative or contributory negligence rule, and an "open and obvious" danger is a defence in many states.
The evidence in these cases disappears fast - surveillance recordings are overwritten on short retention cycles, the hazard is cleaned up, and the incident report is written by the property's own staff. A lawyer's first act is a preservation letter, and that is the reason to call within days rather than weeks. The second question is who actually controlled the premises, which is frequently not the name on the door.
Choose your state. Each link opens the directory page for the city in that state with the most currently published law firms in this practice area; a +n beside the city is how many other cities in the state also have one. The list is generated when this page loads, so a state whose listings have lapsed drops out rather than becoming a dead link.