State Route 266 is a west–east thoroughfare completely within Salt Lake County in northern Utah that connects both sides of the I-215 beltway.

It continues east onto 4500 South, crossing over the Jordan River into Murray and intersecting I-15 in a single-point urban interchange.

SR-266 then descends into a trenched highway, crossing under a mainline railroad carrying freight traffic and FrontRunner commuter trains, a driveway, and the TRAX light rail near Murray North station.

The highway then intersects US-89 before continuing into Murray's suburban neighborhoods, passing several parks and sportsfields.

[3] The State Road Commission designated SR-266 in 1959 as a mostly-proposed roadway, connecting SR-68 and SR-71 with a planned interchange on I-15.