[7] 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 land grant.

From 1851 to nearly 1873, Pacheco was the county’s commercial 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.

For over 20 years, Pacheco was a major shipping port for central Contra Costa County.

[8] The destruction of Pacheco’s Walnut Creek shipping channel occurred gradually over many years and for many reasons.

Man-made ecologic damage eventually combined with a series of fires and floods, as well as an earthquake, destroyed the town and filled the Slough with silt during the 1860s, to ruin Pacheco's growing prosperity just as similar ones had done to the great classic ports of Ephesus and Troy.

[8] Pacheco was subsequently depopulated by the attraction of the nearby town of Todos Santos, later to be known as Concord.

[9] In January 2011 the Martinez City Council voted to annex those portions of Pacheco north of California State Route 4.

In September 2011, Martinez reached a tax sharing deal to pave the way forward for the annexation.

The site claimed that annexing Pacheco would be too costly for Martinez – a city already suffering a deficit, and that property taxes would go up for residents and businesses.

The Contra Costa Times reported that annexation of an area along Interstate 680 from Highway 4 north to the Burlington-Northern Santa Fe railroad crossing was approved by the Contra Costa County Local Area Formation Commission earlier that year.

LAFCO's Executive Officer Lou Ann Texeira said that commissioners would have to take action to terminate the annexation at the September 12 meeting.

City leaders say that the North Pacheco gateway area offers the potential for profit-making development.

The Martinez city council scheduled another vote on the issue, possibly with a larger area.