Officers pulled the 26-year-old woman from her burning car just minutes after she crashed into a sign traveling eastbound on Katella Avenue.
Investigators say the woman, who is from Anaheim, lost control on a curve, and ran off the road shortly before 4 a.m.
She was rushed to an area hospital in critical condition, where she died.
The cause of the crash is under investigation.
No other vehicles were involved in the crash. The identity of the woman was not immediately released.