[3] The sea stack formation was closed temporarily during July 2023 after a cougar was documented, for the first time, climbing on the rock in search of prey.

[4] Measuring 235 feet (72 m) tall,[3] Haystack Rock is composed of basalt and was formed by lava flows emanating from the Blue Mountains and Columbia basin about 15-17 million years ago.

[5] The lava flows came from massive eruptions from a source believed to be what is now the Yellowstone volcanic hotspot, and created many of the Oregon coast's natural features.

[7] Collecting plants or animals is strictly prohibited and to protect nesting birds, climbing above the mean high tide level barnacle line is not allowed.

A variety of bird species, such as pigeon guillemots, common murres, black oystercatchers, and tufted puffins, roost and nest on the rock, raising their young usually between March and September.