Key Characters of Hamlet

Hamlet - Prince of Denmark
Claudius - King of Denmark
Gertrude - Queen of Denmark
The Ghost
Polonius - Claudius' Chief Counsellor
Laertes - son of Polonius
Ophelia - daughter of Polonius
Horatio - friend of Hamlet, from the University of Wittenberg
Rosencrantz and Guildenstern - childhood friends of Hamlet
Fortinbras - Norwegian Crown Prince

The play is set in Elsinore (a.k.a. Helsingor in modern parlance) in Kronburg Castle.