Sacramento City Hall

The City Hall Expansion Project (2003-2008) in Downtown Sacramento revealed a 5,500-year-old archaeological site through geophysical surveys and pre-demolition testing. Excavations uncovered diverse artifacts, offering insights into the area's prehistoric occupation during the Mid-Holocene.

City Hall Expansion Project (2003-2008)
Downtown Sacramento, California
Client: City of Sacramento Department of Public Works

Types of Work:
Geophysical surveys
Pre-demolition Presence/absence testing for archaeological resources in sensitive locations
Construction monitoring
Data recovery of a deeply buried prehistoric site dating to the first half of the Holocene

According to the results of the geophysical surveys, this site was situated on a paleo-sandbar adjacent to an ancient slough. The sandbar, running approximately north-south along the east edge of the block I/J/9/10, was found blanketed with a ubiquitous layer of imported basalt and metavolcanic cobbles, some fashioned into cobble-core tools and multi-purpose ground/battered cobbles, and the rest fire-affected.

This project spanned several years and involved the excavation of 336 cubic meters. The site was exceptionally well preserved, yielding a large collection of faunal remains, cooking stones, large multi-function dart points, stone net weights, bone fish hooks, medicine bowls, a few mortars, many pestles, numerous bone awls, and ornamental stone items, as well as human remains.

Testing results (obsidian hydration and C14 dating) suggest primary site occupation spanned approximately 5,500 years roughly 8500 BP to 3000 BP during the Mid-Holocene, acknowledging both earlier and later intermittent activities.

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