278 fields, 216,245 wells, counted directly from the state's own database. Find the field under a neighbourhood, see how much of it was drilled before anyone kept proper records, and check a specific address against it.
An oil field is not a place on a map so much as a geological formation, and California's were drilled in waves. The field a property sits over tells you roughly when the drilling happened, which tells you which era's plugging practice was applied — and that is the single most useful thing to know about a well you cannot see.
A field developed in the 1920s and built over in the 1950s carries a very different profile from one developed in the 1980s. The counts above make that visible: fields where almost every plugged well has no recorded drill date are fields that were worked before the state kept careful records.
Most of California's wells are in Kern County, on land that is still farmland, oilfield or desert. The fields that matter for homeowners are the urban ones, where the derricks came down and neighbourhoods went up on top of them:
Wells is every well of record in the field, excluding permits that were cancelled before drilling. Plugged means an abandonment was filed — a records classification, not an inspection, and it says nothing about the condition of the well today. Idle wells are not plugged at all: they stopped producing and were never sealed. No drill date counts plugged wells where the state file cannot say when the well was drilled.
Counts come from the CalGEM statewide well dataset dated 29 July 2026 and will shift as the state updates it. Field boundaries overlap in places, and a single property can sit over more than one.
Search any California address against the same database and see every well of record near it, with distances. Free, instant, no account.
Search an address freeCounts derived from the CalGEM statewide well dataset. Cali Well Search is not affiliated with CalGEM or any government agency. California has wells drilled before permitting existed that appear in no state record, and recorded coordinates for older wells carry significant positional error. These figures describe the record, not the ground.