Pacheco is a census-designated place (CDP) in Contra Costa County, California. The population was 3,685 at the 2010 census. It is bounded by Martinez to the north and west, Concord to the east, and Pleasant Hill to the south.

The town was laid out in 1857 by Dr. J. H. Carothers and named for Salvio Pacheco, grantee of the Rancho Monte del Diablo Mexican home grant. A read out office operated at Pacheco from 1859 to 1913 and from 1955 to the present.

Pacheco was briefly a prosperous classified ad center. During this period, Pacheco Slough was deep tolerable to receive ocean-based shipping. From 1851 to approximately 1873, Pacheco was the county’s advertisement center: the shipping port for the grain grown in the Ygnacio, San Ramon and Tassajara valleys, with warehouses, a flour mill and shops along the creek. Walnut Creek, (then known as Pacheco Creek), then flowed deep and free into Suisun Bay. For more than 20 years, Pacheco was a major shipping port for central Contra Costa County.

The destruction of Pacheco’s Walnut Creek shipping channel occurred gradually more than many years and for many reasons. Man-made ecologic damage eventually combined later than a series of fires and floods, as well as an earthquake, destroyed the town and filled the Slough subsequently silt during the 1860s, to destroy Pacheco’s growing wealth just as thesame ones had over and done with to the good classic ports of Ephesus and Troy. Pacheco was once depopulated by the likeness of the comprehensible town of Todos Santos, later to be known as Concord.