State Route 122 is a 7.88 miles (12.7 km) long state highway

State highway

State highway, state road or state route can refer to one of three related concepts, two of them related to a state or provincial government in a country that is divided into states or provinces :#A...

 located entirely in Lewis County

Lewis County, Washington

Lewis County is a county located in the U.S. state of Washington. As of 2010, the population was 75,455. The county seat is at Chehalis, and its largest city is Centralia....

, Washington, United States. The hgihway serves as a loop from U.S. Route 12

U.S. Route 12 in Washington

U.S. Route 12 is a major east-west U.S. Highway, running from Aberdeen, Washington, to Detroit, Michigan. It spans across the state of Washington, and is the only numbered highway to span the entire state from west to east, starting near the Pacific Ocean, and crossing the Idaho state line near...

 (US 12) between Silver Creek

Silver Creek, Washington

Silver Creek is an unincorporated community in Lewis County, Washington, United States. Silver Creek is located along U.S. Route 12 near its junction with Washington State Route 122, west of Mossyrock. Silver Creek has a post office with ZIP code 98585....

 and Mossyrock

Mossyrock, Washington

Mossyrock is a city in Lewis County, Washington, United States. The population was 759 at the 2010 census.-History:The city began as a trading post named Mossy Rock in 1852, after a high moss-covered rock at the east end of Klickitat Prairie...

.

Route description

SR 122 begins at an interchange with US 12 in Silver Creek on a roadway named Silver Creek Road. The highway travels northeast between the western shores of Mayfield Lake and a hillside as it winds through rural Lewis County. Silver Creek Road becomes Harmony Road just before it crosses over the northern tip of the lake, just south of Ike Kinswa State Park

Ike Kinswa State Park

Ike Kinswa State Park in Lewis County, Washington is a camping park in the Washington State Parks. It consists of of forest with of freshwater shoreline on Lake Mayfield. Available activities include hiking, mountain biking, boating, fishing, swimming, waterskiing, windsurfing, wildlife...

. The highway turns south, crossing the Cowlitz River

Cowlitz River

The Cowlitz River is a river in the state of Washington in the United States, a tributary of the Columbia River. Its tributaries drain a large region including the slopes of Mount Rainier, Mount Adams, and Mount St. Helens....

 before terminating at US 12 in northern Mossyrock.

Every year the Washington State Department of Transportation

Washington State Department of Transportation

The Washington State Department of Transportation , was established in 1905. The agency, led by a Secretary and overseen by the Governor, is a Washington governmental agency that constructs, maintains, and regulates the use of the state's transportation infrastructure...

 (WSDOT) conducts a series of surveys on its highways in the state to measure traffic volume. This is expressed in terms of average annual daily traffic (AADT), which is a measure of traffic volume for any average day of the year. In 2009, WSDOT calculated that as few as 610 cars traveled through the intersection with Cinebar Road near the western terminus, and as many as 1,200 cars used the highway near its eastern terminus at US 12.

Major intersections