This account book contains a record of at least some of the financial transactions of the county government during its earliest years. Because the pages are unnumbered, access to entries is provided by numbered streamers.

San Joaquin county was established in 1850 as one of the original counties of the state of California. The Court of Sessions, faced with a considerable indebtedness at the beginning of 1851, established the first property tax in San Joaquin county in May of that year. The amount of the tax was twenty-five cents on every one hundred dollars. The Court also initiated a poll tax of four dollars. The cost of running the county in 1851 was $36,063.60. The new taxes did not raise this amount and, in April 1852, the State authorized San Joaquin county to issue bonds to cover its indebtedness.

Collection is open for research.