The highway was designated as the Yakima River Canyon Scenic Byway by the state government in 1967 and bypassed five years later by a section of I-82 running uphill to the east.

The highway continues north through farms near the community of Pomona and passes the Sundown M Ranch substance abuse treatment center near the mouth of Selah Creek at the Yakima River.

[13] Midway through the valley, SR 821 passes the Canyon River Ranch, an isolated rest area with shops, restaurants, and cabins that is planned to grow into a resort.

[14][15] Further north of the ranch is the parking lot for the Umtanum Creek Recreation Area, with a network of hiking trails connected via a footbridge over the Yakima River.

The highway turns east at Helen McCabe State Park onto Thrall Road and crosses Wilson Creek before terminating at a partial cloverleaf interchange with I-82 and US 97.

[5] SR 821 is designated as the Yakima River Canyon Scenic Byway by the state government, recognizing its natural beauty and recreational opportunities.

[7] The byway passes through shrub-steppe habitats that are home to trout, bighorn sheep, mule deer, and a variety of visiting or permanent bird species.

[7] Sections of the highway are closed for day-long events that are held annually, including a cattle drive in January or February,[22] a marathon and bicycle tour in the spring, and a heritage tractor run in the summer.

[42] The encroachment of residential development from the north forced the Bureau of Land Management and The Nature Conservancy to buy additional properties in the canyon for preservation in the 1990s.

[44] The first year of the campaign was hailed as a success, with two consecutive summer months without a recorded collision and 2,200 police stops for driving violations.