"Great Register" is simply the California name for voter registration records. It probably comes from the fact that the old registration books were huge and very heavy. The pages in the book are arranged alphabetically with each new registration appearing under the previous one.
Photo: San Joaquin County Historical Society
California voter registration began in 1867, the state legislature required each county to record voter information on the local level. The registers contained the voter's name, age, occupation, birthplace, when and where the granting of U.S. citizenship occurred and the court where that took place.
The 1896 Great Register was the first to include detailed physical descriptions: height, complexion, eye color, hair color as well as visible marks, scars, tattoos, physical deformities. By 1910, no physical descriptions other than height were included.
Women first start showing up in 1912, after California passed a state and local suffrage bill.
By 1914, age was no longer included in the voter registrations, but specific street addresses began appearing, as well as gender.
The comments column in the registration books can be very useful. They may include the date when the voter first arrived from another county where they were previously registered; when they left the county and for where; or when they died.
Familysearch has the Great Registers 1866 to 1910. They are indexed and searchable and you will find the site HERE
Jim Faulkinbury, CG has indexed all foreign-born voters in California for the year 1872. You can browse the index HERE.
Below are a few California Counties that have the Great Registers online:
BUTTE COUNTY: 1872 Great Register
MARIPOSA COUNTY: 1872 Great Register
1884 Great Register
1886 Great Register
1912 Great Register
MENDOCINO COUNTY: 1867, 1880, 1890, 1902, 1910, 1920, 1930, 1940
MODOC COUNTY: 1874 Great Register
SACRAMENTO COUNTY: 1866-1871 Great Registers
1877 Great Register
1914 Great Register
SAN DIEGO COUNTY: 1866-1879 Great Registers
SANTA BARBARA COUNTY: 1900 Great Register
SHASTA COUNTY: Great Registers for the years 1866-1884, 1894, 1896, 1900, 1904, 1912, 1926
SISKIYOU COUNTY: Great Registers for the years 1867, 1876, 1877, 1879, 1886, 1888, 1892, 1904
1894 Great Register
TRINITY COUNTY: 1872 Great Register
1885 Great Register
1910 Great Register
TULARE COUNTY: Great Registers for the years 1869, 1888, 1890, 1898
YUBA COUNTY: Great Registers for the years 1867 to 1930