visitor (to a museum, library, etc.)
Used for people who visit a public facility such as a museum, library, art gallery, or similar institution. Not used for personal home visits.
This museum receives over 100,000 visitors annually.
The number of library visitors is increasing.
来場者 is used for visitors to an event or venue (e.g., concert, exhibition), whereas 来館者 is limited to facilities like museums or libraries.
Compound of 来 (rai, 'come'), 館 (kan, 'building, hall'), and 者 (sha, 'person'). The kanji combination directly conveys 'person who comes to the building'.