County Highway edit
| Number | Southor west terminus | North or east terminus | Length (mi)[1] | (km) | Cities or Areas served | Notes |
|---|---|---|---|---|---|---|
| A1 |  SH-28 near Mud Lake
|
 SH-22 near Lily Hot Springs
|
18.207 | 29.301 | Monteview. | known as Monteview Highway. |
| A2 |  US 20 near Macks Inn
|
 I-15 near Dubois
|
999.999 | 1,609.342 | Kilgore. | |
| A3 | US 20 near Idaho Falls
|
 SH-48 near Lewisville
|
999.999 | 1,609.342 | Lewisville | known as Lewisville Highway. |
| A4 | I-15 near Lewisville
|
SH-48 in Ririe
|
999.999 | 1,609.342 | Ririe | known as Ririe Highway. |
| D1 |  SR-23 at Utah state line south of Weston
|
 US 91 near Downey
|
999.999 | 1,609.342 | Oxford, Clifton, Dayton, Weston | |
| G3 | near the Magic Mountain Ski area |  US 30 in Hansen
|
999.999 | 1,609.342 | Rock Creek Canyon, Magic Mountain Ski area. | Rock Creek Scenic Byway |
| K1 |  SH-55 near Caldwell
|
 I-84 in Caldwell
|
999.999 | 1,609.342 | Caldwell | 10th Ave South |
| K3 | SH-55 near Caldwell
|
 SH-19 in Caldwell
|
999.999 | 1,609.342 | Caldwell | Farmway Road |
| P1 |  SH-7 in Ahsahka
|
 SH-3 near Kendrick
|
999.999 | 1,609.342 | Southwick, Cavendish | Formerly State Highway 7 |
| P2 |  US 12 in Lewiston
|
 US 95 near Sweetwater
|
999.999 | 1,609.342 | Lewiston | An alternate highway to Lewiston |
| P3 | US 12 in Myrtle
|
US 95 near Craigmont
|
999.999 | 1,609.342 | Gifford and Reubens |
County Highway System edit
The County highway system in Idaho currently has 11 signed county routes. These routes are assigned a letter prefix depending on their location throughout the state, Much like the County Highway System in California. Though there are not specific milepoint logs for the county highways with the Idaho Department of Transprotation, there are some references to these highways in the state milepoint logs, and on the official Idaho State Highway Map[2] and in the current versions of the Rand McNally Road Atlas.[3]
The Prefix Regions currently used are:
- A = Eastern Idaho (Idaho Falls)
- D = Eastern Idaho (Preston)
- G = South Central Idaho (Twin Falls)
- K = Southwestern Idaho (Caldwell)
- P = North Central Idaho (Lewiston)
Idaho County Highways edit
A1 edit
County Highway A1 or A1 passes through Monteview in eastern Idaho. The highway is 18.290 miles long. Its northern terminus is with State Highway 22 (Milepost 53.155) near Lidy Hot Springs, and its southern Terminus is with State Highway 28 (Milepost 17.700). This road is known as STC 6755 on the Idaho state Milepoint Log, and locally as Monteview Highway.
A2 edit
County Highway A2 or A2
A3 edit
County Highway A3 or A3
A4 edit
County Highway A4 or A4
D1 edit
County Highway D1 or D1
G3 edit
County Highway G3 or G3
K1 edit
County Highway K1 or K1
K3 edit
County Highway K3 or K3
P1 edit
County Highway P1 or P1
P2 edit
County Highway P2 or P2
P3 edit
County Highway P3 or P3