The museum in the basement of downtown D.C.'s Ford's Theatre is closed after a water leak flooded the facility with about an inch of water.
President Abraham Lincoln was assassinated while attending a play at Ford's Theatre in April 1865.
National Park Service crews have isolated and stopped the source of the leak, but haven't yet determined its cause.
The museum is closed; it's unknown when it will reopen.
No artifacts in the museum have been affected by the flood, the NPS said. Curators are on site to monitor humidity levels.