The cones are berry-like, 5–10 mm in diameter, blue-brown with a whitish waxy bloom,[2] and mature in about 18 months.

[9] J. occidentalis can be found in the Western United States—specifically southeast Washington, eastern and central Oregon, southwest Idaho, northeastern California and extreme northwest Nevada, north of 40° 30' N latitude, east of the Cascade Range.

It usually occurs on dry, rocky sites where there is less competition from larger species like ponderosa pine and coast Douglas-fir.

[2] In very exposed positions at high altitude, it can assume a krummholz habit, growing low to the ground even when mature with a wide trunk.

In the John Day area of Oregon, it competes for sunlight among ponderosa pines at the bottom of some deep side canyons.

In the past two decades, sagebrush steppe ecosystems have witnessed an expansion of Juniper throughout the western U.S.[10] This alteration of vegetation change can be associated with the decreased fire frequency, overgrazing of livestock, and an alteration of climate that transformed into a more wet and mild climate.

[10] Fire scar data was collected and dated to display the expansion of western juniper.

[12][13] While not common as a lumber source, Oregon State University has sponsored research into the use of western juniper for commercial applications such as sign posts and guard rails.