The largest park in Yreka, Greenhorn Park has been built around an expansive reservoir sourced by Greenhorn Creek. Trails weave through the surrounding hillside, lapping the lake, while fishermen take advantage of both off-shore and boat fishing. A large picnic area, play structure, open field and a new log cabin information center and restroom are located at Upper Greenhorn. Along the south side of the lake there is old gold mining machinery and a small ghost town. Lower Greenhorn maintains a community soccer field, play structure, large picnic areas, horse-shoe pits, and two restrooms. Lake access is available from Lower Greenhorn and both sections have their own parking areas.

Activities at Greenhorn Park include Yreka Youth & Adult soccer during the fall and spring at Lower Greenhorn; cross-country meets, mountain bike races, fishing tournaments; and city-wide festivities for Yreka's 4th of July celebration.

There are two separate entrances for Greenhorn Park: one for Upper Greenhorn on Greenhorn Rd and one for Lower Greenhorn on Ranch Ln.

Upper Greenhorn Park - Directions: From I-5, take exit 773 toward Yreka. Turn on Moonlit Oaks Ave toward Yreka. Turn right on Hwy 3/Fort Jones Rd/S Main St. Turn left on Greenhorn Rd. The entrance to Upper Greenhorn Park is .6 miles down Greenhorn Rd. A large parking located at the end of the drive.

Lower Greenhorn Park - Directions: From I-5, take exit 773 toward Yreka. Turn on Moonlit Oaks Ave toward Yreka. Turn right on Hwy 3/Fort Jones Rd/S Main St. Turn left on Ranch Ln. The entrance to Lower Greenhorn Park is two blocks down Ranch Ln and a parking lot is available.