The Nov. 6 election will decide the presidential race, as well as many federal, state and local races and ballot measures.
For people unable to register in person, California last month launched its new online voter registration system, available at www.registertovote.ca.gov.
The system allows citizens whose signature is already on file with the Department of Motor Vehicles to submit their registration form to their county elections office electronically.
The system was set up as the result of a law authored by state Sen. Leland Yee, D-San Francisco/San Mateo.
Yee's office said this week that about 544,000 Californians had registered to vote via the new system since it started in September.
About 59 percent of eligible California citizens voted in the 2008 presidential election, according to Yee's office.