New complaints may be filed in any of the Divisional Offices of the Central District. However, the civil case number will identify the proper location for subsequent filings.
A typical civil case number consists of the Divisional Office location [Southern Division in Santa Ana (SA) or Eastern Division in Riverside(ED); no initials are used for Western Division in Los Angeles], an indication that the case is a civil filing (CV), the last two digits of the year of the filing of the initial document, the case sequence number, the initials of the assigned district judge, and the initials of the assigned magistrate judge.  For example, CV-01-020 BCD (EF) means that the case was filed in the Western Division, is a civil case, was filed in 2001, was the 20th case filed that year, is assigned to the district judge with the initials BCD, and is assigned to the magistrate judge with the initials EF. (Note that the initials of the assigned magistrate judge are in parenthesis.)
Subsequent documents (capital habeas corpus petitions and civil cases), with certain exceptions, must be filed at the location where the district judge is located. The certain exceptions are non-capital habeas corpus petitions, pro se civil rights cases, social security cases and other matters referred to a magistrate judge; documents filed in those cases must be filed at the location where the magistrate judge is located.