There are 28 routes assigned to the "A" zone of the California Route Marker Program, which designates county routes in California. The "A" zone includes county highways in Lassen, Plumas, Shasta, Siskiyou, and Tehama counties.
A1
County Route A1, more commonly known as Route of the Olympic Torch, is a county route in Lassen County, California.
County Route A1 runs from Route 36 near Susanville to Route 139 near Eagle Lake. It was originally named Eagle Lake Road.
Major junctions
This route still exists as a bypass from Susanville for north–south motorists, but it is no longer signed as such.
A2
County Route A2 or Susanville Road is a county route located in Lassen County, connecting SR 299 and SR 139.
Major junctions
A3
County Route A3 or Standish–Buntingville Road is a road in Lassen County connected to U.S. Route 395, and functions as a bypass for northbound traffic around Susanville. At its northern end it is signed for Reno (via US 395), and its southern end for Lakeview, also via US 395.
This route still serves as bypass for north–south 395 motorists, but is no longer signed as such.
Major junctions
A5
County Route A5 or Bowman Road is a road in Tehama County connecting State Route 36 in Rosewood and I-5 in Cottonwood
Major junctions
A6
County Route A6 or Long Road is a road in Tehama County connecting Manton Road in Dales to Forward Road in Manton. Along the way it has an intersection with SR 36.
Major junctions
A7
County Route A7 is a road in Tehama County connecting Live Oak Road and SR 36 in Red Bluff.
Major junctions
A8
County Route A8 is road in Tehama County connecting SR 99 in Los Molinos and SR 36 in Red Bluff.
Major junctions
A9
County Route A9 is a road in Tehama County connecting Round Valley Road in Paskenta and SR 99 and Interstate 5 in Corning.
Major junctions
A10
County Route A10, known locally as "Everett Memorial Highway", is a long county road in Siskiyou County near Mount Shasta. It runs from Ski Village Drive in the town of Mount Shasta City to a dead end at the level on Mount Shasta.
The highway, completed in 1958 at a cost of $980,000 and designated in 1959, was originally built to provide access to the Mount Shasta Ski Bowl, which was destroyed by an avalanche in 1978. Today, the highway provides access to Mount Shasta for climbers, skiers, and anyone wanting access to the mountain.
In wintertime, the road is kept open only to the U.S.F.S outpost at the level.
Major junctions
A11
County Route A11 or Gyle Road is a county route located in Tehama County and connecting Interstate 5 and CR A8 near Tehama.
Major junctions
A12
County Route A12, known locally as the "99-97 Cutoff", or more commonly, "the 97 cutoff", is a two-lane rural highway with a length of . A12 begins in the west at its junction with Old 99 Highway, which was once US 99. Just a few dozen yards to the east, it intersects Interstate 5. Its eastern terminus is at US 97, north of Weed.
One mile east of the Interstate junction, it passes through the tiny village of Grenada, the only population center of any merit along the route. further east is the burg Mayten, which consists only of a convenience store, a church, and an elementary school.
The route is heavily used by travellers and truckers southbound on Interstate 5 who wish to use US 97 northbound en route to Klamath Falls and points north. This route saves over than if the alternative routing via I-5 to Weed, then north on US 97 was used. Hence, the local name "97 cutoff".
The western two-thirds of the route passes through agricultural areas, and is very reminiscent of two-lane farm roads in California's Central Valley. However, the eastern portion is very scenic, passing through an area with towering dark red crags and buttes to the north.
Major junctions
A13
County Route A13, also known as Walker Memorial Road, is a road in Plumas County connected to SR 36.
Major junctions
A14
County Route A14 or Graeagle Johnsville Road is a road in Plumas County connecting SR 89 and Johnsville.
Major junctions
A15
County Route A15 or Portola McLears Road is a road in Plumas County connecting SR 89 and SR 70 in Portola. On its northern end, after passing through the Old Town commercial district of Portola, A15 passes the Western Pacific Railroad Museum.