"Great photos, not many of those races have appeared before.  Kirker Creek runs through the west edge of the property thus that reference.  Camp Stoneman was the name of the facility during WW II and used by the U. S. Army as a staging are for troops headed overseas.  Since it was located close to Suisun Bay which leads to the SF Bay, it provided an excellent place to stage troops before boarding ships.  Adjacent to Camp Stoneman (decommis- sioned after the war) was the Concord Naval Weapons Station which was active from WW II until 1999 when it was turned over to Contra Costa County.  It was an ammunition storage facility throughout its life and was active during WW II, Korean and Vietnam wars.

During the two years races were held over the abandoned roads of Camp Stoneman (April 3-4,1965 and April 2-3, 1966), it was called the Contra Costa GP.  It was a dangerous road course due to the many obstacles just off the pavement and hidden by the tall weeds.  Concrete foundations and other debris were lurking if a driver went off course with potentially serious results."

(11-4-13)   More from Gary:

"After a bit more research, Camp Stoneman was to the east of Concord Naval Weapons Station a couple of miles.  It was bordered on the north by Highway 4 (still there) and the streets Railroad Ave. (on the west) and Harbor St. (on the east).  That whole area is now houses in the city of Pittsburg.  There is a small public park by the name of Stoneman West Park in the middle of where the race course used to be.  By the way, the course was the same for each of the two years the race was held.  An overhead aerial view shows no evidence of the large industrial plant seen behind the crashed white car on the hay bales in one of the photos."

(11-9-13)   From Rich Blackmarr:

"Competition Press & Autoweek's Western Edition insert for May 8, 1965 has a report on the Norcal season opening April 3-4, 1965 SCCA Regional event at Pittsburg's Kirker Creek Raceway that was billed as the "Contra Costa Grand Prix."  

Of note during the weekend's events was high race car attrition due in part to pavement on the old military service roads breaking up badly in at least three of the 2.1 mile race course's eleven turns.  Apparently the events were quite popular as a crowd of 27,500 spectators is noted.  

The CP&A report confirms the race by race class winners already posted.  From an event I attended a month after the Kirker Creek races, the May 7-8-9 Laguna Seca Regional/USRRC race program lists Regional race entrants that correspond well with Gary Horstkorta's race car/driver IDs for the Kirker Creek race photos from Mike Fuchs."